Inside the Castertown MegaMall, the biggest mall in the world, live the night children - runaways, abandoned kids, kids who got lost and were never found. They only come out at night, after all the shoppers are gone.

When thirteen-year-old Jule Devereaux visits the mall after the mysterious disappearance of her aunt, she becomes a pawn in the war between two gangs of night children: the Castertown Crazies, led by the stalwart Tick Stiles, and the Dingos, whose leader is the batty Burt Arno. What the night children don't realize is that the megalomaniacal owner of the MegaMall, billionaire Amos Zozz, knows all about them. To him, they are vermin - 'rats' living in his beautiful mall - and he has plans to exterminate them. Julie, Tick, and Burt must join forces if they want to survive...