At the supermarket, Entrèe has a barcode on his butt scanned, and finds out that he is two days away from his "best before date", after which he will supposedly turn to mush. After a day of trying desperately to "turn back the clock", Entrèe switches places with Peri, pretending that Peri is Entrèe, with only a day to live. Peri, buying the deception, decides to destroy all of "his" stuff, and tells his friends what he really thinks of them, as read in "his" diary. When the time finally comes, Peri realises the truth, and Entrèe, instead of turning to mush, gains a hair-like growth of mould.

Entrèe's lucky stone goes missing and Peri is determined to find out who took it.

Entrèe makes promises to all his friends to get anything he wants but has no intention to keep the promises he makes. He soon makes one promise he regrets.

Peri gets a new pet, Pistachio the buppy. When Pistachio runs away, Peri is heartbroken. After visiting Compuhorse, Peri decides to not feel any emotions anymore, becoming "Compu Peri". His friends decide to try and snap him out of it.

While trying to find batteries for a "Mr. Jigglesworth" toy, Peri and Entree find a pair of walkie-talkies, and use them to pull pranks on the other mutants. Soon after, though, Entree starts using his walkie-talkie to ask Peri for help with everything, causing Peri to discard his in anger.

Entree, desperate for respect, finds a helmet in the Doctor's lab, which teaches him kung fu. Entree is quickly corrupted by his new-found talent, and takes over the entire town, beating up anyone who challenges him. Peri uses the helmet to learn how to make ballon shapes, using this skill to defeat Entree.

Entree is bored and decides to have fun on the island. Peri, Joe and Patricia stop him and he accuses them as fun wreckers. The next morning Entree jet-skis the island to Antarctica and the island is attacked by Yetis. Entree sees that Yetis can do whatever they want and decides to join them.

Entrée time–travels with Patricia and Peri to find out why Two–Legs Joe doesn't like him.

Bowled Over - Peri wants to know what he's good at. After running from Two-Legs Joe, Peri and Entrèe find a secret room for bowling, Peri realizes that he was born to bowl. However, in trying to prove his bowling ball can be used for other activities, Peri is frustrated by the results and throws the ball into the volcano. After this, an alien civilization, the Pinnians decide to take over the island and treat the mutants like slaves. By realising these aliens have a kinship with bowling, Peri decides to confront them doing what he does best.

Mister Smarty Smarts, tired of the incompetence and ineptitude of the inhabitants of the island, creates a device to make everyone smarter. His utopia is soon ruined when everyone's intelligence goes way past his. After being treated like an idiot, Smarts decides to make everyone unintelligent again.

Peri and Entrèe want to thank Joe for everything he's done for them and the island. After asking Compuhorse what they could do to make him happy, they decide to give him Peri's arms for a day. Joe is pleased but grows too fond of Peri's arms and doesn't want to give them back.