Willow has to overcome her fear of heights, when she gets snatched by a magpie and taken to its nest. The rest of the Insectibles will have to find a way to rescue her and to get an important Shrinkinator's part.
When Adilla tricks a human kid into dropping a giant lollipop in the yard, the Insectibles have to stop the onslaught of sugar-crazed ants getting themselves stuck to it -- without getting caught themselves.
The Insectibles pretend to be a group of actors in order to gain entrance to the roach's base camp and retrieve a Shrinkinator part. But Zak's delusions of acting grandeur - and a surprise visit from Adilla - ends up turning all of their plans into an off-Broadway blunder.
The Insectibles are thrown for a loop when they encounter a bar magnet in the yard - set as a trap for them by Adilla. Thanks to Grampa's tinkering, the magnet causes some unexpected chaos as they're carted to Adilla's tower by Hye and Lo.
Willow, determined to prove she can take care of herself, gets trapped under a glass still bearing traces of pink lemonade. High on sugar and running out of time as the glass heats up, she finds she needs the help of her friends... just as they need her quick thinking to get her out in time.
Grampa's invention of a growth formula turns out to be a brain-switching potion instead! Adilla steals the formula after Zak and Grampa have already switched bodies and, not realizing its true effects, ends up switching bodies with her henchmen! A problem like this will require a lot more brain-switching before everything's sorted out!
A primitive tribe of flies is discovered by the Insectibles. They welcome Willow, to be the guest of honor. Little do we realize it's to become a sacred sacrifice to their god -- a big backyard bug zapper.
Adilla is called away and leaves her daughter Lidia in charge. The Roach camp is soon thrown into anarchy, until Lidia finally settles on a mission for her minions: kidnap Zak and make him fall in love with her. What could possibly go wrong?
Zak is faced with an apocalyptic problem as his team turns into brainless zombies during their trek through the mushroom patch. Zak is forced to team up with Adilla to find a solution to the strange plague, all while defending themselves against the approaching horde inside an old water pistol.
Spring has sprung, and with it the sudden appearance - and disappearance - of countless butterfly cocoons! Where did they all go? Chowser is determined to find his pupa brethren and leads a daring rescue once he discovers that they were taken by Adilla's goons for brainwashing. Will Chowser be as determined, though, once he finds out that he's incapable of becoming a butterfly himself?
The shed is threatened by a mysterious worm with a metal jaw, forcing the team to try and ward it off with special sonic stakes. But when the worm breaches the perimeter, will they be able to save their home?
When Zak takes advantage Chowser's admiration he gets a taste of his own medicine when some ants make him Chowser's Hand Maiden. When Zak fears the ants plan to eat Chowser he has to save his best bud from the lap of luxury.
The Insectibles name is being sullied across the yard as a group of lame knockoffs travel from village to village committing crimes while pretending to be Zak, Willow, Syd and Chowser. The team has to find these felonious fakes and put an end to their reign of slander.
When Zak gets an entire family of microscopic dust mites to do his bidding, he convinces his friends that he has "magic powers." But when he tries to use his MAGIC against Adilla, his invisible army gets scared and takes off - leaving Zak and Willow in the lurch!
Willow starts up her own detective agency helping bugs solve mysteries all over the yard, but she has to keep it a secret from her friends. All is going great until he friends hire the "famous detective" to find out what Willow is doing all the time. Now, Willow is stuck playing both herself and the detective until her friends confront her for a big crazy finish.
After Zak's arm starts going through a series of bizarre malfunctions, the team discovers that Gramps is sleep-tinkering and has to find the cure before it's too late - or Gramps may lose his memory forever!
Gramps orchestrates a camping trip with Zak in order to get a deep, dark secret off his chest. But his efforts to bare his soul are continuously interrupted by the Roaches, sent to spy on the pair by Adilla.
When Zak finds a prototype jetpack in Gramps' lab, he can't resist strapping it on and taking flight. It soon becomes evident, though, that he's not as skilled a flier as he thinks he is. Can Willow help Zak learn to fly, or will his recklessness blow their chances at getting a Shrinkinator part?
Syd gets more than be bargained for when he takes over as the yard's mail carrier and starts mixing up packages while hitting on his customers. Things get messy when he makes a date with three women in the same night.
When Gramps' test of the Shrinkinator goes wrong and turns Zak and Gramps invisible, Zak has to find a missing part to fix everything -- unfortunately, the missing part is on Chowser who's the prisoner of the roaches.
When Hye and Lo get zapped with a ray that makes them smart, Gramps discovers that their newfound brilliance could be the key to fixing the Shrinkinator. They agree to help, and everything goes smoothly until Zak arrives and mistakes the Roaches helping for them harming his team.
The team brings Gnat back to the shed after finding him unconscious by a blown fuse box. As Gnat is nursed back to health while Gramps works on the Shrinkinator, the team investigates a mysterious wire leading into the yard. But what does it lead to?
When the roaches find a magic 8-ball keychain in the yard, they welcome it as their wise new leader - abandoning Adilla in the process. Adilla has to team with Zak so they won't destroy the Shrinkinator at the 8-ball's behest.
When Zak's arm is upgraded with the ability to project a hologram of himself, Willow convinces him to prank Syd and Chowser. But when Zak gets into some real trouble, his friends don't believe it's for real!