John Felton meets evil late one Monday morning when the doorbell rings. Standing on the front porch is a stranger. He wears expensive running shoes and a baseball cap and calls himself Richie. He tells John his car has stalled and asks for help. An altercation at the gas station leads to a shocking crime as violence begets violence. At the end of this harrowing day, John returns home to find Richie ensconced in his living room, chatting up his wife. The evil has somehow seeped into his life. Thus begins the transformation of an unremarkable husband and father of two into a desperate man willing to go to any length to protect his family from the darkness that threatens them.