Moving from Los Angeles to tiny Crabtree, Michigan, is the last thing thirteen-year-old Kat Dylan wants to do. Crabtree's seen better days and isn't what you call welcoming. Worse, the move means living with her gruff Grandpa Nick, the town's police chief, and having to look after her little brother, Alec.

And that's before Kat and Alec find themselves in the middle of a bank holdup by the Monster Gang-four robbers in monster masks. Before the heist is over, the kids lose their cash and Alec comes within a hair of losing his life. When it is all over, Grandpa Nick goes to jail, accused of being one of the robbers himself.

Suddenly, this boring little town isn't so boring anymore. Kat's determined to find out who the men are behind the masks, and she's going to need help. But exposing the robbers could have big consequences. The deeper Kat goes, the more she learns life is about making choices, including some that are a matter of life and death.