While Lord Mitchell gains power from orbs retrieved by his minions, Kirby prepares himself for battle by training to be a gatekeeper with Mitchell Prime.
When the Buckets family uses the orb to take their annual family vacation in another dimension, they find themselves in a labyrinth run by Fish's old guinea pig, Mr. Mac N' Cheese.
Kirby discovers he and Mitchell are partners on the Forest Hills police force and are assigned to take down a pair of robbers who just might be Kirby’s parents.
Kirby and his friends find themselves in a bizarre alternate dimension where "rotten" kids are mulched and then regrown to be fresh versions of themselves.