Bob Ho (Jackie Chan) is a CIA undercover agent. He is in relationship with Gillian (Amber Valletta) who has 3 children before, and decides to retire after moving next to her house. Since Gillian's father is in hospital, Bob takes responsibility of taking care of 3 children. And when those 4 are threaten by a Russian terrorist, Bob faces his toughest challenge in his life: working as a stepfather and a spy agent at the same time.