Kappa Mikey is a parody of Japanese anime. Mikey Simon is a teenage actor from Cleveland, Ohio who wins a scratch-off card contest and a trip to Japan to star in the country's formerly popular anime series, "LilyMu." As a result, the show becomes number one in the ratings, and Mikey becomes Japan's biggest anime star. The show focuses mainly on the actors and producers' lives off the set, as Mikey's adjustments to his new environment.
At a video rental store on Halloween, Mikey comes across a "creepy, unmarked" DVD, and after watching it, he and his friends are cursed. Their one way to break the curse is to assist a girl named Samoa to find her gobstopper in a haunted house, looking out for clues from the DVD itself.
Mikey decides that he wants to free a captive squid while Guano uses a new gel on his fur.
Mikey and Lily get a retainer from the Bracemaster; Guano disguises himself as a panda for a LilyMu episode.
Mikey puts an artificial-intelligence chip in a motorcycle, creating a talking bike with attitude. Lily becomes popular among the Viking community after she steps up efforts to improve her public image.
Ozu lets his rivalry with another show's producer overshadow a friendly game of baseball.
After eating a radioactive sandwich Gonard gains superintelligence, and his friendship with Mikey is strained. Meanwhile, Lily, Mitsuki, and Guano compete for endorsements.
After Mikey floods the set, the crew has to film on location while avoiding the perils of the wilderness and Kappa as well.
The cast panics when Ozu hires a script doctor who is famous for killing off characters; Guano becomes a talk show celebrity.
When the gang goes to Mount LilyMu, everyone but Mitsuki can go on the bullet train, since Mikey cannot find Mitsuki's ticket. On the train, Mikey hears mumbles and finds Mitsuki tied up. Mikey convinces the gang to help find Mitsuki, and whoever kidnapped Mitsuki. In the subplot, Yes Man quits after a fight with Ozu.
Ozu wants to get the Masked Tanuki, the local superhero, on his show as a ratings boost. Mikey and Gonard rob their own studio to lure him in, only to lure in the Cat Burgler, who kidnaps them as a means for revenge. Meanwhile, Lily and Mitsuki try to solve the mystery of Guano’s apartment.
Ozu and his crew go undercover as students and faculty at the local Lebaniku High School, in order to figure out who’s behind a DVD piracy ring, making illegal copies of their show. Mikey, unable to fit in with any of the cliques, winds up with two nerds. Gonard becomes the Lebaniku football teams’ secret weapon against their rival.
A pair of mystical friendship bracelets magically switch Lily and Mitsuki’s bodies, and they agree to live the other’s life for a while, so Mistuki can finally date Mikey. Lily ends up working with a pair of environmentalists named the Do-Gooders. In the subplot, Gonard and Guano are cursed by a tiki idol.
Mikey opens a Kappa Mikey-themed restaurant, which does lousy until Gonard starts preparing dishes for it. A rival restaurant nabs Gonard and hypnotizes him into making dishes for them instead. In the subplot, Lily is caught showing hatred toward babies, so Ozu forces her to take care of a baby for one day to regain LilyMu’s reputation.
Mikey, Gonard, Guano, Mitsuki and Lily go to camp.
Mikey gets lost in Yoyogi Park and meets a Werepuff, a monster who eats peoples' clothes, and Mikey turns into one when his pants are eaten off. Lily feels suddenly attracted to him, and they soon become a celebrity couple. The only way to cure him is if he eats the fur of the original Werepuff before dawn.
Mikey finds a karaoke machine run by a robotic genie. But Mikey insults the genie, causing it to put a curse on him and his fellow LilyMu cast members so that they can't stop singing.
Since the cast of LilyMu is still unable to speak except in song, their show is cancelled. They wonder about what to do with the rest of their lives. Will they be cursed forever?
Ozu orders Mikey to write the first chapter of his memoirs for a magazine tomorrow, with the help of Guano, but things go haywire after Mikey starts making up lies about his accomplishments. Meanwhile, Gonard finds out that he could actually be royalty.
Like the heroes of the famous Japanese film The Seven Samurai, the cast responds to a distress call from a poor boy and LilyMu fan named Riku, whose playground is about to be destroyed by an evil Garbage Man to make way for a landfill. However, used to doing live shows, the five are under the impression that this is just another gig, and Riku thinks they are real heroes instead of actors.
As in Mark Twain's novel "The Prince and the Pauper," Mikey decides to take time off from being a superstar and trades places with an ordinary citizen who looks just like him.
Guano doesn't know how to finish a LilyMu clip show.
Mikey gets in trouble playing a game of golf, while Lily and Mitsuki try to join a country club.
When the cast tries to perform an episode "live", everything goes wrong.
Mikey falls in love with the actress in a kabuki play, unaware that it is actually Mitsuki understudying for her father after he breaks a leg, literally. Meanwhile, Gonard falls in love with popcorn, and it develops into an addiction.
When Lily's favorite clothing designer visits the set, Mikey and Lily compete to win his approval for their contrasting fashion lines. Meanwhile, Gonard becomes obsessed with developing his abs on Ozu's exercise machine.