When Ross, a 33-year-old female cop, goes on an undercover operation, she is followed by her deep cover cop or 'ghost' whose identity isn't known to other undercover members of the unit. Harry Earles is there to protect her under all circumstances. They seem to make a good team, Ross with her instincts and the Ghost with his experience. But Harry is a psychopath who starts to stalk her. When Harry discovers that Ross has a terrible secret hidden in her past he threatens to use it against her and Ross is left to battle against Harry alone...