Stuck at home and bored, a retiree takes a job at a 24-hour convenience store. On her third night at work a customer finds her on the floor behind the register, face down in a pool of blood. Detectives determine that her last customer was also her killer. Only two witnesses saw that customer.

The phone rings in the middle of the night and on the other end of the line, there is the awful sounds of an attack. The couple who received the call rush to its source only to discover a horrific scene. Two teenage sisters, from Taiwan studying English for the summer have been viciously attacked in their basement apartment.