The Big Bash is the twentieth episode of Season 5.
Cosmo and Wanda wake Timmy up to tell him that Cupid’s having another one of his legendary parties. Timmy wants to know why that matters to him. Apparently anyone who’s anyone is invited to a Cupid party…but someone must have said no because Cosmo, Wanda and Timmy are on the list!!
After Cosmo, Timmy, and Wanda arrive at Cupid's mansion for his big party, Cupid announces that this year's game would involve a scavenger hunt, wherein they have to use their imagination, fashion, and smarts. The reward for winning is a couple seconds of "rule free wishes." It is soon discovered that Remy Buxaplenty and Juandissimo were also invited, the former displeased upon seeing Timmy and his godparents. He announces his plan to uses those wishes to get rid of Timmy's fairies. Meanwhile, Juandissimo bets Cosmo in wager of a nickel and Wanda; if Cosmo wins, he gets the nickel and keeps Wanda, but if he loses, Wanda becomes Juandissimo's wife. When the game starts, Remy wishes for all the contestants to fall asleep who quickly do so, all except for Timmy who had wished up an anti-magic bubble to remain immune to Juandissimo's magic. They quickly hop on their time scooters and start their time travel journey.
The list said to find:
The biggest egg ever laid
Container 07-9-B from the Apollo 15 mission in 1971.
The world's largest banana that was found in King Kong's clutches in 1933.
Pot of Irish gold from the 15th Century.
An 18th century Danish that was found with Napoleon Bonaparte.
The Grand Treasure of the Peruvian Pyramid from Ancient Peru
Timmy finds the first item by going back to when the dinosaurs still roamed the Earth. He picks up a large egg and gets out in time before getting violently attacked by a dinosaur.
Briefly in the lead, Timmy then travels to the moon during the Apollo 15 mission in 1971, where he finds Container 07-9-B. Unfortunately for him, as he holds up the prize, Remy floats by and snatches it away from him.
After Remy's dishonest act, Timmy quickly travels to 1933 to the movie "King Kong." However, before he can think of a plan, Remy has already hired a woman to distract the giant ape, who then hands over the gigantic banana in return.
Hurriedly, Timmy rushes to 15th century Ireland. Surprisingly, the Leprechaun willingly gives them his pot of gold, blurting out the bet that Cosmo and Juandissimo made through a limerick: Everyone thought old Cosmo was dense, for betting his wife for five cents, if she's gone he'll be sad, if she finds out she'll be mad, I'm betting the pain is intense. Infuriated that Cosmo bet her for a measly nickel, Wanda turns red and shouts at Cosmo, ready to murder him. Luckily, Timmy steps in and reminds them that they are in the middle of a scavenger hunt and they need to get going.
They then go to 18th century France, where a painter is painting a picture of a Napoleon Bonaparte. After Napoleon finishes posing his signature pose for the artist, he takes his hand out of his shirt and pulls out a Danish. However, before he can eat his pastry, Remy(who was the painter) grabs it.
Seeing that Remy already had three items and he only had two, Timmy rushes to the last item on the scavenger hunt list. After traveling to Ancient Peru, Timmy sees that he was too late--Remy had already taken the gems on the pedestals and was going back to Cupid's house. After Remy and Juandissimo poof back to Cupid's home, Timmy notices something strange--he explains to Cosmo and Wanda that in most movies with temples and pyramids that have treasures hidden in them, a bunch of booby traps go off once someone takes the treasures. Timmy deduces that Remy and his godfather must not have gotten the actual treasure--and after taking a small cylindrical can covered in dirt, a booby trap goes of. Timmy and his godparents manage to escape and then poof back to Cupid's house.
When Timmy gets back to Cupid's mansion, the result is a tie. But the truth is, they were in fact tricked into doing Cupid's grocery shopping for his brunch. The two boys agreed to put aside their differences and declare a truce, at which their godparents use their magic to bring in the various historical figures they encountered during the hunt as payback. Timmy and Remy both tell the figures to "Get him!" The figures then chase Cupid down to beat him up (With Cupid saying "Good thing I am wearing a diaper."). They then celebrate with some of Cupid's breakfast.
Wanda, having discovered the bet between Cosmo and Juandissimo, also gets mad because Cosmo wagered her for five cents. While Timmy and Remy are enjoying the food and drink, Wanda poofs up all the things that they saw all the way to the end of the scavenger hunt to chase Cosmo and Juandissimo as payback for using her as a wager, and the items chase and crush them.