Emily has mysteriously returned home to her mother and stepfather, after being missing for over a year – and something came with her.

A graduate student and martial-arts expert rents a room in a house owned by a single mother who lives there with her son. A local street gang is trying to recruit the son, but the new tenant tries to help the boy’s mother keep him out of the gang. When they learn of this, they target both the mother and her new tenant.