The story is set in London 1882, where jingle writers Cavis Appythart (played by Bob the Tomato) and Millward Phelps (played by Larry the Cucumber) are admiring the work they've been doing for Durling's Dental Wax. However, while Millward is proud of what they've been doing, Cavis, on the other hand, is depressed, because their careers aren't going anywhere. The reason for this is because Cavis is concerned of the lack of love and peace that's been going on in London. Cavis then says that if he could do one thing, he could really teach all of London how to love, but he doesn't know how to do that. Cavis then looks in the newspaper that Millward is holding, which shows an ad for inventions by the famed inventor Seymour Schwenk, which gives him an idea.
Later, Cavis and Milward have rented a theater from Millward's uncle, Ebenezer Nezzer (played by Mr. Nezzer), thanking him for letting them borrow the theater. Ebenezer then tells them that he'll think of something before he says goodbye to them. After Ebenezer leaves, Cavis and Millward are now waiting for Seymour to show up, which Cavis fearing that maybe the new invention that Seymour had failed to work, or that he sold it someone else, or that it blew up. However, he is proven wrong when Seymour Schwenk (played by Pa Grape) shows up in his brand new invention, a rocket-powered car (which looks identical to the one from Chitty Chitty Bang Bang). Pa Grape then explains to Cavis and Milward how it works, with Milward asking if he would take it for a spin. Just as Millward is about to get in the car, Cavis stops him, telling him that their play entitled "The Princess and the Plumber" opens on Christmas Eve, but they have one problem because Milward never finished writing it, because he is stuck on a rhyme, the word in question being "possum". Cavis then asks Seymour if he brought the equipment necessary for the play, which Seymour did, before Cavis then tells Milward to finish the script for the play.
When Millward says that he'll try, Cavis responds with, "No, we're not gonna try, no, we're gonna do it this time!" Cavis then says that he's not going back to writing ads for Durling's dental wax again, before he starts singing "This Is Our Big Break", singing about how he and Milward are going to get their chance at stardom. When Millward asks what's in the box, Cavis tells him that in this modern age, it's not enough to have a great story anymore but to show the audience something that they've never seen before, which is electric lights on the scenery itself, as opposed to just on the outside of the building. When Millward asks Seymour if he can do that, with Seymour answering that it's a fire hazard. Cavis then says that when it's your big break, sometimes you just have to take chances, which Winston (played by Jean-Claude Pea) agrees with. Cavis then sings once again about taking a chance because they're running out of time. Cavis then tells Milward to find that rhyme. Cavis then asks Winston if he has any luck with the crown prince, to which Winston replies that he's on the phone with him right now. Seymour is surprised when he realizes that Cavis is referring to the crown prince himself, Prince Frederick, which Cavis confirms, "heir to throne and England's number one theater critic". Cavis is certain that a good word from the prince will make the show be a hit in London. When Seymour asks if the prince is coming, Cavis answers that he will when he sees what a spectacle the show is as well as the fact that it stars his favorite actress, Effie Pickering (played by Madame Blueberry). Seymour is surprised that Effie is in the musical, but Cavis nervously replies, "Not yet exactly". Winston then pipes up that Effie is in Cavis's office, which surprises Cavis.
Cavis then enters his office, where he finds Effie Pickering waiting while drinking tea. Cavis is glad to see Effie, while Effie tells him to cut to the chase. Effie then tells Cavis that he has two minutes to convince her to be in "The Princess and the Plumber" (which she mispronounces as "The Princess and the Plum"). Cavis corrects her, telling her that "a plum is a fruit, while a plumber is a skilled laborer who works on pipes". Cavis then explains the plot of the story to Effie, telling her that the play is about a sad princess and a kindly plumber and the power of love. He then explains that on the night before Christmas, the Princess's sink backs up so she calls for the Plumber, which unbeknownst to him, the Princess's pipes are actually magic pipes. Back in the main room, four peas dressed up as fairies sing that they are the fairy peas and that they like to eat strawberry cheese, which Milward praises, saying that it's going in. Cavis then explains the rest of the story to Effie, while Winston is still talking on the phone with the Prince. When Cavis tells Effie that the show will have electric lights, Effie tells him that the Royal Theater has electric lights too, Cavis tells her that the show will have lights on the scenery, which surprises Effie, before she asks if they can do that, to which Cavis confidently replies "Oh yeah". Effie then asks if the crown prince will be there, because the show will fail without a good word from the crown prince. Cavis is about to say that the prince will be there, before he comes back out into the main room again, where Winston is still talking with the crown prince.
Millward is still trying to find a rhyme for 'possum', when Cavis and Winston confront each other to which Cavis tells him to tell him that the prince is coming, with Winston answering, "If Miss Pickering is in, the Prince is in". Cavis then says that if the Prince is in, then Miss Pickering is in as well, before he returns to his office again and tells Effie that the Prince will most definitely be at the show, to which Effie then consents that she will be the in show, which Cavis is happy about. Cavis then tells Effie that a lot of people in London show a lack of love and that a spectacular show will help to teach them to love. Effie then leaves after that, with Cavis satisfied that Effie is in the show at last. Winston also confirms that the Prince is coming as well. Cavis then tells Millward that they need the rhyme for the show, before Millward is finally able to come up with a rhyme for 'possum', which is 'blossom'. Millward then proceeds to sing, "Oh, Plumber, you dropped your possum / Yes, Princess, I think it is true / I was hoping our love might blossom / But the possum is eating my shoe", which Cavis praises as gold. Cavis and Millward then sing about it being their first big break and that they will be sure to teach all of London how to really love on Christmas Eve. However, the duo then discover a flyer advertising a Christmas pageant being held at St. Bart's Church, which is to be on the same day as Cavis and Milward's play.
At St. Bart's Church, a young boy named Edmund Gilbert (played by Junior Asparagus) is overseeing production for the pageant, trying to get the other kids to help out with the pageant, such as setting up the flyers for the pageant, and getting the costumes all ready. Edmund's father, Reverend Gilbert (played by Dad Asparagus), shows up, asking Edmund how it's going, to which Edmund answers that it's going pretty good, before stating that they're a little behind schedule but tells him that they'll be sure to catch up if he helps out. Reverend Gilbert then tells Edmund that a Christmas pageant doesn't have to be a huge spectacle, before he explains to Edmund the story of Christmas, about how God sent to Earth his only son Jesus to give love to everyone on Earth. Reverend Gilbert then tells Edmund that the Church Committee decided that he would use the Star of Christmas in the pageant, as long as he's really careful with it. Edmund is happy, telling his dad that it will be really great. Reverend Gilbert is about to leave, when he nearly bumps into Cavis, who was overhearing everything in the church.
Cavis then leaves the church, trying to assure himself that it's just a bunch of kids putting on a church play, before he starts wondering what a Star of Christmas is. At that moment, a historian named Arthur Hollingshead (played by Archibald Asparagus) overhears what Cavis said and explains to him about the history of the Star of Christmas, before he rushes off to tell the newspapers about the discovery that the Star of Christmas will be appearing in the Christmas Pageant at St. Bart's Church. Cavis says that the Post Gazette won't pay any attention to a little Christmas Pageant, but he is proven wrong when the story is published anyway in the Post Gazette. Milward then reads the story about the Star of Christmas being used in the Christmas Pageant, before elatedly stating that they should go see it, before Seymour states that it's the same night as "The Princess and the Plumber". Cavis then says that in order for their show to be a big hit, they'll need a good word from the Prince, just as the phone rings, before Milward goes to answer it. The caller turns out to be Prince Frederick, who says that he won't be coming to see Cavis and Millward's play after all, which shocks Cavis.
Despite all that's happened, Cavis states that this was their big chance and that they were going to put on a show so beautiful and so well-lit that it was going to show London how to love. Cavis then indignantly shows Milward and Seymour the door, at first mistakenly opening the closet door, before he opens the correct door. Seymour tells Cavis to shut the door and that they're with him, which Cavis is happy to hear. Cavis then says that the show must go on before saying that they need the prince in order for their show to be a hit. At first, Seymour suggests that they kidnap the Prince, before asking Milward if that's legal, to which Milward answers that it isn't. Milward then says that the only way for the Prince to really give the show a good word is that it's better than the Star of Christmas, which Cavis realizes it a good idea, saying that it's their only chance to save the show. Cavis then says that they have to make the show even more spectacular with bigger songs, bigger sets, and most of all, lots more lights.
Soon, the sets and the lights are now being worked on, before Millward has the players take it from the top. Effie as the Princess thanks the Plumber in song for coming, before the Plumber (played by Jimmy Gourd) tells the Princess to show him where the problem is and that he'll fix it on the double. Milward then praises the song, which Cavis agrees with, before asking Seymour how he's doing with the lights, to which Seymour replies that he got more lights but there isn't any more room on the scenery for them. Cavis then thinks a while before he sees one of the peas balancing one of the lights on his nose, before he says, "Who says we can only put them on the scenery?" which makes Seymour nervous. The Plumber then sings "Your pipes are corroded, the water won't drain, your toilet exploded, you're flushing in vain". Cavis then asks Seymour how it's going with the lights. When Seymour tries to light on light bulb that's on the head of one pea, the light bulb shorts out, which causes that pea to feel dizzy before falling off the stage. Cavis then decides to give the Prince another call.
While Cavis is on the phone with the Prince, Seymour has him wear a light bulb hat that he's working on. Once Cavis has gotten hold of the Prince, he explains to him that the play is more impressive now, telling him that the songs are bigger, the sets are bigger, and that they'll have electric lights on the costumes as well. Cavis is then interrupted by the Prince who tells him to sing the jingle for Durling's dental wax, which goes "For happy Jills and happy Jacks, using Durling's famous dental wax". After Cavis finishes talking with the Prince, Milward asks Cavis what he said, to which Cavis answers that the only way the Prince would come to the show is if they had a Star of Christmas. Milward then asks how they could have a Star of Christmas, and that there's only one and that it's at the church, and is wondering how they could have it if there's only one. Of course, this gives Cavis an idea, at the same time that the light bulb on the hat he is wearing lights up. Seymour was successful in getting the light bulb hat to work, before noticing Cavis's devious expression.
Meanwhile, at St. Bart's Church, Reverend Gilbert is talking with Moyer (played by Scooter Carrot), thanking him for helping with the ladies temperance league dinner, to which Moyer quips that for being temperamental, they sure can eat. Reverend Gilbert then asks Moyer if he put the Star of Christmas in the cabinet, which Moyer says that he did but he is rather nervous about leaving it out all night, before saying that there are desperate characters who would love to get their hands on it. Reverend Gilbert tells Moyer to "have faith in your fellow man" and tells Moyer that anyone who wanted the Star would have to go through him first. Moyer then says that his fighting days are behind him now, even in spite of Reverend Gilbert reminding him of when he was second runner-up for Prize Fighting Champ. Reverend Gilbert then says that they'll lock up the church good and tight before he leaves afterwards, leaving Moyer all alone in the church. It turns out that Cavis and Milward had snuck into the church before the doors were locked, before they proceed to approach the cabinet where the Star of Christmas is kept. Milward says that he doesn't feel very good about the Star, but Cavis tells him that they're not stealing the Star, but borrowing it, and once they're done with it after the Prince gives their play a good word, they'll bring the Star back. After opening the box that the Star of Christmas is kept in, Cavis is amazed by it, while Milward says that it looks like a turtle. Cavis then says that he doesn't care if it looks like a chicken on a bicycle and that it's what the Prince was to says, so he tells Milward to grab it so that they can leave. Milward then grabs the box, but while leaving, the tablecloth gets hooked on the back of his shirt, which causes him to unknowingly pull the tablecloth from behind him, which surprises Cavis when he sees what's about to happen.
From outside the church, there is a loud crash, which wakes up Moyer, who asks who goes there. Cavis and Milward try to escape from the church, before they find themselves face to face with Moyer, who then discovers that they've got the Star of Christmas, which angers him. Cavis and Milward run as fast as they can to escape from Moyer's wrath, but they find that the front doors for the church are locked, so they have no other choice now but to run up the attic stairs, with Moyer close behind them. Cavis and Milward find that there are no more stairs, before Cavis notes that the lift at the top of the attic must go somewhere, just as Moyer is still closing in on them. When Cavis hops onto the lift, it then falls down while he is on it, before falling past Moyer, who then goes back down the stairs after him. The lift then crashes down to the bottom of the attic. When Milward asks Cavis if he's okay, he winds up bumping into a shelf that some bells are kept on, which causes the bells to fall onto the basket that pulls the lift back up with Cavis still on it, going past Moyer again, before he starts going up the stairs once again. Once Cavis is back up to the top of the attic again, he is rather dizzy, before noticing a ladder in front. When Milward is apprehensive about climbing up the ladder, Cavis asks him if he would rather stay with Moyer, to which Milward then starts up the ladder, with Cavis behind him. Moyer is able to catch up to the ladder, which then starts to tilt backwards with Cavis and Milward on it, before Cavis and Milward end up falling out the top window of the church and land into a laundry cart that was being pulled by a trader (played by Scallion # 3). The cart then rolls backwards, with Cavis and Milward laughing about how they're lucky to be alive after falling out of the bell tower. Cavis then asks if they're moving, before the cart then crashes off-screen after that.
Back at the theater, Cavis and Milward have returned while looking very bruised and beat up from what happened, while the Plumber asks if they want to talk about it. Cavis answers "no", but says that he does want to see the closing number in the most spectacular musical that London has ever seen. Cavis then recaps that the Plumber has defeated the Monkey King in a plunger duel while the Sugar Plumber Fairy has turned the wicked Building Inspector into a newt, and that the Princess realizes that the Plumber is the one that she's been in love with all along. The final song then starts up, with the Princess and the Plumber singing that they've loved each other all along and that their love will flow like water running down the drain and will shine like a star, showing the Star of Christmas, which looks suspiciously like a turtle. Seymour then turns on the lights that have been placed on the scenery and on the player's costumes, but unfortunately the excess power for the lights causes one of the switches to emit a spark which then catches the curtains on fire and engulfs the theater in flames, as everyone evacuates, but the Star of Christmas also ends up getting lost in the flames as well.
The next morning, the theater has been burned down, with Cavis and Milward disappointed that their one chance to put on a spectacular play has literally gone up in flames. To make matters worse, they are then approached by Moyer, who has the Constable (played by Jerry Gourd) arrest Cavis and Milward for theft of the Star of Christmas, and are thrown into jail as a result. Cavis is upset that he and Milward have to spend Christmas Eve in jail, before Milward then sits down to play a harmonica that he apparently had with him all along. Cavis then says that all he wanted was to teach London how to leave, before he and Milward hear a gruff voice say "Teach London? How to love?" There, they meet a gruff scallion prisoner named Charlie Pincher, who asks the duo how they were going to do that. Cavis then answers that they were going to do it with a spectacular stage show with great songs, costumes, and lots of electric lights, before Mr. Pincher starts laughing at the prospect of using light bulbs to teach London how to love, before sarcastically telling them that they could teach London to read with light bulbs if they were in night school. Mr. Pincher then tells Cavis that he's more likely to teach a horse to fly than to teach London how to love. When Cavis asks Mr. Pincher if anyone has been nice to him, Mr. Pincher answers that someone will be nice to you when they want something from you. Mr. Pincher then goes on to tell Cavis that he's real nice to his actors when he needs them, but that isn't love, then says that giving up something for someone when they don't deserve it, when there's nothing in it for you is love. Then, he says that going to someone when he needs help but you won't get anything back is love. Of course, Mr. Pincher then says that he never saw anything like that around where he came from. Mr. Pincher then concludes that you can't teach a man to love because it's not in his nature, before he then has another good laugh about the prospect of using light bulbs to teach London to love.
The Constable then approaches then jail cell, telling Cavis, Milward, and Mr. Pincher that it's dinnertime, then wishes them a happy Christmas Eve, before telling Cavis and Milward that they have some visitors, which Cavis thinks is Seymour. Edmund and Reverend Gilbert then enter the room, which Cavis and Milward are surprised about, as Cavis asks what they're doing at the jail. Cavis then thinks that Edmund and his father are mad at him and Milward about the Star of Christmas, but Reverend Gilbert tells him that they're not going to yell at him, before explaining that it was Edmund's idea to come and bail Cavis and Milward out of jail. He then explains that he's been teaching Edmund about how God gave to us his only son Jesus, and that he's named as Emmanuel, God with us, because he loved us. When Cavis asks what that means, Edmund replies that it means that they aren't going to press charges. Reverend Gilbert adds that they're forgiving Cavis and Milward, and that the judge says that they can go. Cavis and Milward are happy about this, while Mr. Pincher is a little bit bitter about what he just witnessed.
Once Cavis and Milward have been released from jail, they are happy that Edmund and his father have bailed them out from jail. Cavis then says that since he and Milward don't have anything else to do, they can go see the pageant at the church, but Reverend Gilbert says that the pageant starts in 10 minutes and that it took them more than to hour to get to the police station. When Cavis asks how they're going to get back in time, Reverend Gilbert asks that they weren't, before Cavis realizes that Edmund and his father gave up the pageant for him and Milward. Of course, Seymour then shows up in his rocket car once again, before wondering why Cavis and Milward why they aren't in jail. Milward then tells Seymour that it's time for him to let him take the rocket car for a ride. Soon, Cavis, Milward, Edmund, and Reverend Gilbert are now seated in the rocket car, with Seymour explaining to Milward that Rockets 1 through 5 got burned up arriving at the police station and that Rockets 6 through 10 should be able to get them to the church, before warning Milward not to use Rocket 11 because it never has been tested. Seymour also adds that the brakes only work on the ground, with Cavis saying that he didn't know that that was optional. When Seymour asks them where they're going, Milward says "We've gotta make it to the church on time!" before the rocket car then takes off, with Seymour quipping that it just gets weirder and weirder.
The rocket car then zooms down the streets of London, before Milward is able to steer the car in order to dodge some wagons, but the rocket car crashes into a wagon being pulled by the same trader that was pulling the laundry cart, to which that cart was full of hats. The rocket car then crashes into a bakery, to which Cavis has doughnuts on his eyes, Reverend Gilbert and Edmund are up to their necks in a pile of bread, and Milward has lemon danishes covering the lenses of the goggles he is wearing. The rocket car next crashes through a bank, which picks up a confused banker, which scares Reverend Gilbert. Milward is about to take a shortcut through the crystal palace, but the others dissuade him from it so he goes the other way. With the rocket car now down to Rocket 10, the group is now approaching the drawbridge, but unfortunately for them, the drawbridge then starts lifting up, just as the last rocket has now started to die, leaving the group dead in the water. Reverend Gilbert and Edmund thank Cavis and Milward for trying, with Cavis disappointed that they're all out of rockets. However, Milward notes that they're not completely out of rockets, so he activates Rocket 11, which the others tell him not to do, but he says, "Cavis, the show must go on!" before Rocket 11 then fires up, sending the rocket car forward and propelling them up into the air as they fly over the entire city of London, right towards the church.
At the church, Moyer is greeting everyone who has come to attend the Christmas Pageant, including Prince Frederick (played by Mr. Lunt), before Moyer tells him that he's really in for a treat tonight. The rocket car then starts to descend towards the ground, right towards the church before it starts bouncing across the ground, just as Moyer then has gotten everyone inside the church, before he notices the rocket car coming towards the church. The rocket car then crashes to the ground, sending Cavis, Milward, Edmund, Reverend Gilbert, and the banker flying towards the church doors, to which Moyer jumps out of the way. The group is then able to make it inside the church after that. Once the group has landed inside the church, everyone inside then starts applauding after that. Edmund then says that it's time to put on a pageant, before Cavis tells him that they don't have the Star of Christmas, but Edmund tells him that they do and that he didn't steal the real star of Christmas, which confuses Cavis. Edmund then tells him that the Star of Christmas isn't something you can steal, and that it isn't something at all, referring to the baby Jesus. Cavis and Milward understand this, before Edmund tells them that he does need a new Star of Bethlehem and asks them to help me out, to which Cavis and Milward agree to do.
Soon, the pageant has started, with Edmund narrating that Joseph and Mary have come up from Nazareth to Bethlehem, and that they were expecting a baby. He also explains that after the baby was born, he was wrapped in cloth and placed in a manger because there was no room for Mary and Joseph in the inn. Edmund also narrates that out in a nearby field, some shepherds were watching over their flocks of sheep, when they were approached by an angel, which frightens them. But the angel tells them not to be afraid because he brings them news that Christ the savior has been born. Edmund then explains that after Jesus was born, three Wisemen came from the East to Jerusalem and asked where the one has been born to the Jews and that they saw his star and have come to worship him. However, nothing happens, before Cavis realizes his and Milward's cue. Seconds later, Millward is on the prop star, with Cavis using the lift from the attic to lift up the star, before Edmund concludes that all this took place to what the prophet has said; that she will give birth to a son and that they will call him Emmanuel, God with us. Everyone starts applauding, while Cavis watches on, saying that he understands, which Reverend Gilbert is curious about, before Cavis states that there is only one story that can teach us how to love, which is the story of the first Christmas. Hoewver, when Cavis hops off the lift, it also causes Milward to crash to the floor after that.
After the pageant is over, Cavis and Milward hop out from the church, before they are confronted by Ebenezer Nezzer, who is not happy from hearing about what happened to his theater. Mr. Nezzer then tells them that they are to work for him in his factory until it's paid off, just as Edmund and Reverend Gilbert show up after that. After Mr. Nezzer leaves, Prince Frederick then shows up, praising Edmund for his performance, before telling Cavis and Milward that that star was their finest work since dental wax. However, Moyer then shows up, which frightens Cavis and Milward again, before Moyer shows everyone that he has found the real Star of Christmas, which had been in his sock drawer the whole time. Cavis then asks him what they took, to which Moyer answers that it was their other most famous relic, the Turtle of Damascus, which most people believed to be a hoax, before Milward tells Cavis, "Told you it looked like a turtle". Reverend Gilbert says that all things considered, things worked out pretty well, before Prince Frederick tells Cavis and Milward that he wants to talk to them about their next production, but Cavis says that he has one more thing that he needs to do first. Later, it turns out that Cavis and Milward have gone back down to the police station to do something nice for Mr. Pincher. This involves Milward hanging up a Christmas wreath on the wall and gives Mr. Pincher a Christmas present, while Cavis gives Mr. Pincher a plate of cookies and hot cocoa, before warmly telling him "Merry Christmas, Mr. Pincher". Mr. Pincher is happy that someone is kind enough to show him love and do something for him out of kindness, before the episode then ends.