The villains of the Kids Next Door, lead by Father, join forces to resurrect the Ultimate Evil, Grandfather, a tyrant who once ruled the world many years ago when most of the villains were themselves kids. However, Father disgraced him that he can't even try to destroy the KND and the Villains were quickly betrayed when they are turned into Senior Citizombies, creatures that are immortal and can transform any living creature into one of them and slaves who are forced to make Tapioca to refuel Grandfather so he can find and destroy the Book of K.N.D.
as Nigel 'Numbuh 1' Uno / Hoagie Pennywhistle 'Numbuh 2' Gilligan Jr / Numbuh 101 (voice)
as Kuki 'Numbuh 3' Sanban (voice)
as Wally 'Numbuh 4' Beatles / Mr. Fibb / Toilenator / Joaquin / Tommy Gilligan (voice)
as Abigail 'Numbuh 5' Lincoln / Former Numbuh 11 - Cree Lincoln (voice)
as Chad Dickson (voice)
as Crazy Old Cat Lady/Gramma Stuffum (voice)
as Mr. Boss / Mr. Fizz / Benedict Wigglestein (voice)
as Fanny 'Numbuh 86' Fulbright / Computer (voice)
as Stickybeard (voice)
as Knightbrace / Mr. Wink (voice)
as Father (voice)
as Patton 'Numbuh 60' Drilovsky (voice)
as Monty Uno (voice)
as Grandfather (voice)
as Count Spankulot (voice)
as Rachael T. 'Numbuh 362' McKenzie (voice)
as Sector Z Numbuh 0.1 - Bruce (voice)
as Sonya - Number 83 / Lee - Numbuh 84 (voice)
as Numbuh Zero / Lenny - Sector Z Numbuh 0.4 (voice)
as Additional Voices (voice)
as Additional Voices (voice)