After being chased by the Wunny Sharbit, Peri and Entree get stuck up a tree. Entree makes a hanglider out of his chicken wings and promises to come back for Peri. But when a mysterious mutant hangs around town and becomes friends with Entree he forgets about Peri. After some time however, the new guy starts to torture Entree with a game called "you have betrayed me and now I will have my revenge".
After a busy day of helping the other mutants, Patricia creates "Mrs. Motherly", a computer system designed to help everyone on the island with everything. Mrs. Motherly's drones go off to help, but they soon start doing everything for the mutants. Tired of this, Patricia, Entree and Peri team up to shut down Mrs. Motherly.
Sick of the constant abuse Entree heaps upon them, his stomach, heart and brain suddenly jump out of his body, abandoning him. Entree then ingests Peri, having him fulfill the roles of his AWOL organs. After a few false starts, the arrangement becomes satisfactory for both of them. However, Entree's organs return, having outstayed their welcome by annoying everone else on the island.
After experiencing painful itching, Peri becomes a chrysalis, emerging to reveal a beautiful pair of butterfly wings, which entrance anyone who looks at them. Entree takes advantage of this by charging the other mutants food to look at Peri's wings. Mister Smarty Smarts tells Peri that Entree is using him, convinces him to banish Entree, and starts using him for his own nefarious goals.
After a series of bad nightmares, Peri decides to use one of the Doctor's dream machines to enter his subconcious and confront his nightmare monster. However, once inside, he discovers that the toaster-headed monster isn't such a bad guy after all. Together with Entree and Patricia, they become "Dream Gladiators", protecting the dreams of all the mutants on the island.
While picking on a Whirrel named Ed, Entree and his victim fall off a cliff. The landing causes their brains to pop out and rebound into each others' heads. Entree quickly enjoys his new life as a Whirrel, and the unassuming Peri enjoys Ed's pleasant attitude. Entree is then ordered by a group of Whirrels to kill himself for his crimes against Whirrel-kind.
After Entrèe laughs at Fuzzy Snuggums' latest attempt at exploring, Peri tells him that it's Fuzzy's dream. He shows Entrèe that Patricia and Joe have dreams too, but Entrèe scoffs, saying his only dream is to eat something delicious. After eating a pickled egg from the Doctor's fridge, Entrèe passes out. After waking up, he starts to hear a voice in his head telling him to do things.
After being tormented by Peri and Entree, Smarty Smarts and Joe go to their "happy place", only to find out that it is the same place. Realising that they share a mutual dislike of the annoying duo. The two become friends, pooling their resources to deflect Peri and Entree's antics, and pulling a few pranks of own.
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.
Patricia is constantly distracted by the antics of the other islanders. She quickly loses her temper, threatening to beat everyone up if they don't let her work in peace. When Patricia tries to move on with her story, she experiences writer's block, and realises that her friends crazy antics actually gave her inspiration.
After a particulary exhausting day of stomping, Joe wakes up to find out that he can no longer stomp. Peri and Entrèe decide to help Joe find his stomp again, by bringing him to his "happy place". Meanwhile, Smarty Smarts capitalises on Joe's lack of stomping by using his "Cyber-Stomper" machine to terrorise the village.
Entrèe becomes obsessed with getting everyone to like him. An accident with a pair of very tight jeans makes him realise that the milk from his top-right udder, "Nugget", is very tasty. Everyone loves the "Nugget" milk, and Entrèe soon becomes incredibly popular, to the point where he shuns Peri. However, everyone else then becomes addicted to the milk, and when "Nugget" runs dry, they chase after Entrèe.
Patricia goes on vacation, reluctantly leaving Peri and Entrèe as housesitters. Peri and Entrèe end up turning the house into an indoor jungle, and when Patricia gets back, she is captured by her pet Molesters, who have turned into a savage tribe by their new environment. Peri and Entrèe mount a rescue attempt, but discover that the Molesters have actually made Patricia their queen.
When Peri and Entrèe accidentally cause a Whirrel to destroy half the town, Joe loses his temper, demolishing the other half. The other mutants tell Joe that he needs to control his temper. Joe, hurt, leaves, declaring Peri and Entrèe the new mayors. In solitude, Joe hears from the bird on his back, Lord Wingus Eternum, who teaches him how to control his anger.
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.
Peri and Entrèe want to know why Patricia is so upset and become "The Smile Squad", trying to cheer her up in outlandish and fruitless ways. When that fails and they make her even more upset, they decide to use a brainscan machine to look into her mind and see what she's thinking. They find out that Patricia feels lonely because she's the only none-mutant on the island. After some thinking, Peri comes up with the perfect plan to make her feel like one of them.
Entrèe is tired of walking, working and moving of any kind and wishes he could just be lazy for the rest of his life. While walking through the jungle he meets Slouch Potato a lazy mutant who teaches Entrèe how to get a chump to do everything for him. After annoying Peri with his laziness, Entrèe is left lying in the middle of town where he starts to grow roots that stick him to the ground.
After Peri and Entrèe accidentally shoot themselves into the sky with one of Fuzzy's transportations, Entrèe uses his chicken wings to stop him and Peri falling to their death. However, he crashes through a building and loses control. After they crash through a makeup store, a clothesline and a wig shop (completely changing their appearance) they land in the tree house of Princess Pony, who believes they are magical fairies. After learning she'll give them everything they ask for in return for dances or fairy tales, Entrèe decides to use Princess to get everything he wants.
After escaping Princess Pony's tickle attack, Peri and Entrèe find an old golf cart. Entrèe repairs the vehicle, replacing the engine with the brain of an evil robot. After naming it Gordon, Peri and Entrèe travel around the island with their new car. After a few days of driving, Peri and Entrèe don't want to drive again for a while. After they abandon Gordon in the jungle, he decides to cause trouble.
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 are looking for someone to join them in a game of Bucket-Stick-Fruit-Ball, but nobody wants to play. The terrifying Princess Pony Ape Hands is the only one who wants to play. However, she plays too rough so Peri and Entrèe quickly try to ditch her. Princess throws a major temper tantrum and decides to smash the old nuclear reactor.
In search of fun in the lab, Peri and Entrèe find one of the doctor's journals, which supposedly tells what the purpose of Peri is. The friends go to visit Mister Smarty Smarts hoping he can read Peri's purpose to them, but it turns out he can't read. He lies and says Peri was created to be the best friend of Entrèe.
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.