Andy and Danny prank call several people claiming to be the local DJ in charge of the "Beat the Bomb" contest. One of the people they prank, Martin, takes it seriously and thinks he actually won $512. To avoid embarrassing him they have to raise $512. The method they use: they claim that "Bumpo the Monkey Dance Dancing Monkey" is sick. Andy has to dress up as Bumpo and act sick.
It starts with a crowd of people, some holding signs, chanting "WE WANT BUMPO!" and facing Danny who is dressed as a clown, who is in front of a caravan. He goes into the caravan to meet Andy and informs his friend that "They, uh, want Bumpo?". Andy says "I got that impression." Andy narrates that although his practical jokes are a riot, the riot outside the caravan was not part of the plan.
Andy and Danny were writing on cards at a table, working on a plan to increase their cash flow. The radio was playing "The Monkey Dance" which was a dance craze, which Andy found "idiotic". Danny started dancing like a monkey. Andy pointed at Danny and said that he wouldn't be caught dead doing the Monkey Dance. Jen came in and asked what he had against monkeys, and remembers how he once got lost in the zoo and made friends with one. Andy replied that that was the result of a poorly planned prank. Danny and Freida said that the monkeys were in the news and Andy had a monkey suit in his closet. Andy was about to explain why he was listening to Triple B, but was interrupted by laughter on the radio. It was the introduction of a game called Beat the Bomb, which involved stopping a bomb to win money. Jen, Andy, and Danny really liked that game. After thirty-two dollars, the game stopped, which disappointed Andy, Danny, and Jen. The announcer said that the prize would be delivered by Miss East Gackle and Bumpo the Monkey Dance Dancing Monkey. Jen said grumpily that thirty-two bucks was not much. Danny noted that nobody had the guts to keep the clock ticking past fifty bucks, and Andy said that was because he'd never gotten to play. Jen asked if he really believed he could play, and Andy said that it was likely as he and Danny had written a lot of postcards with his name and phone number and were about to send them to Beat the Bomb. Jen just gave a "whatever" response.
Outside the post office, they found a long line. Andy and Danny mailed the letters into a caravan. Danny pointed out that with lots of people sending postcards the whole town was going nutty over Beat the Bomb (however they could have been non-Beat-the-Bomb-related postcards, at least some of them.) Andy then said he thought he had a plan to take advantage of the situation. The boys then went home.
At home, Andy told Danny to phone Mrs. Weebles. Danny phoned Mrs. Weebles with the help from a phone book and Andy pretended on the phone to be Dynamo D from the Triple B and that it was time to play Beat the Bomb. The boys then revealed the joke and Andy said "All pranks are registered trademarks of Master Prankster Productions. Any unauthorized uses of pranks is clearly copying" and joined in laughing with Danny. The next person they thought of to prank was Craig. For Craig, Andy pretended that instead of more and more money being offered, there was less and less, leading to minus sixteen dollars. Craig pointed out that wasn't how the game worked. On minus sixty-four dollars, Craig shouted "Stop!". Andy then said that the bomb beat Craig and he owes Triple B sixty-four dollars. Craig didn't have sixty-four dollars, so Andy said that he could give them his bike that he got for his birthday instead. Craig asked how they knew what he had for his birthday, and Andy and Danny revealed the joke, hung up, and burst out laughing. Danny asked who could be more gullible than Craig and Andy said that there was only one person: Martin Fonwick. They phoned Martin, and pranked him, asking if he was ready to beat the bomb. Martin didn't know what "beat the bomb" meant. Andy explained. Mr. and Mrs. Fonwick looked worried upon Martin's saying "A random phone call offering me money?". Martin said that it was his lucky day. Andy then started the fake game, and it went on for a while as Danny had a hard time finding the bomb sound affect. Martin said "Stop!" and danced with joy as he believed to have one five hundred and twelve dollars. Danny got tangled in film, and Mrs. Fonwick started crying. Martin said the money was right on time as his dad had a giant toilet roll on his big toe. Andy and Danny realized they might be in trouble, as unlike with the previous two victims they hadn't said "gotcha".
At school, Martin danced like a monkey. Everyone was celebrating Martin's "win". Lori told Andy that he was using the money to get people into his website for free. Lori then asked Andy out, but no tricks, as she only went out with people who had class. Danny pointed out that Martin didn't win any money. The athletes then cheer for Martin. Andy then fake-congratulated Martin. He then suggested Martin wait until he get the money before he started spending it. This made the other students laugh. Martin then wanted to call the radio station, and to halt him, Andy said "Let me call them for you." Andy then admitted to Danny he didn't have a plan. The boys were stumped, but tried to think of a plan. Andy reviewed what they had to do: give five hundred and twelve dollars to Martin, get the mascots and convince them to come and deliver the money, and make sure Lori doesn't find out about the prank so she would still want to go out with Andy all before Friday. Danny was still worried, but Andy thought it was a good challenge. The boys then dressed up in suits and advertised a water tower on the streets. Andy then tried to sell shampoo in the mall: fifty dollars a bottle, pretending to be the famous fashion designer Pierre LeCous. When that didn't work, Andy and Danny then dressed in drag and tried to sell cookies door-to-door.
Eventually they only earned seven bucks, but they still needed five hundred and five. They then asked Mush the delivery man how to get five hundred and five dollars, a beauty queen, and a dancing monkey by Friday. Mush replied that they were "slashing the pepperoni pretty thin", which inspired Andy to use what he had and stretch it as far as possible. He then asked Danny for a top hat, a broom, a fake mustache, and a whole lot of pizzas.
In front of the caravan, Danny banged the trashcan with a broom. The man in the caravan told him to be quiet as he was attempting to play real music. He then chased Danny down the street. While the man was away, Andy sneaked into the caravan. The man came back and then Mush came with pizzas. This surprised the man as he didn't order pizza. While Mush and the man talked, Andy changed the time on the clock. The man then took in the pizzas and noticed it was "ten o'clock" already and his "show" was over. He signed off, and Andy giggled. The man then left, and Andy watched him leave. Andy then sneaked in and pressed a button marked "ON THE AIR". He pretended to be Dynamo D, and fake-announced that Bumpo was ill. He then gave the thumbs up to his sidekicks.
That's where the we-want-Bumpo crowd came into things.
In the present, Andy wonders what Mush would do. He then tells Danny to stall by telling the crowd Bumpo's on his way. Andy then sneaks out of the caravan and dashes home. He runs out of the house with a monkey suit, surprising Freida. Al thinks at least he's getting his exercise. Lori comes and asks Andy to go for ice cream. Andy wants to but is too busy and pretends he has to drop his mom's fur coat at the cleaner's. Lori asks why Freida would want her fur coat during a heatwave. Andy lies that the heatwave has caused their air conditioning to malfunction and now their house is freezing. Andy arrives, dressed as Bumpo, and dances. The people then pay him.
The mayor hugs Andy-Bumpo, and wants to buy Bumpo. Andy says that Bumpo is not for sale. Andy gets out of costume and gives the money to Martin, awkwardly trying to explain why Miss East Gackle and Bumpo aren't there. Martin is angry as he wants the mascots. Danny and Andy then plan to pretend to get Miss East Gackle, but find only Miss Esther Gackle. They use Andy in the monkey suit and Esther as Miss East.
At the stadium, there is a paintball war happening. Andy and Lori are dating. Lori likes Andy's "maturity". Martin then announces "Miss East Gackle and Bumpo the Monkey Dance Dancing Monkey". Andy and Danny then pretend to have allergies and leave. Mush "delivers" Esther.
They then perform. Craig wonders why "Miss East Gackle" looks so old. However, when they get changed, Lori finds them out.