The show revolves around the main kid operatives of Sector V - Numbuh One (Nigel Uno), Numbuh Two (Hoagie Gilligan Jr.), Numbuh Three (Kuki Sanban), Numbuh Four (Wallabee Beatles) and Numbuh Five (Abigail Lincoln). Their mission is to fight crimes against kids, such as homework and flossing, committed by adults, senior citizens, teenagers, and other "evil" children. They make up what is known as Sector V of a worldwide organization called the Kids Next Door.