The teenage girl was the first victim. Her throat cut to the bone, she didn't stand a chance. Her mother was the second. She, at least, had time to fight back. Briefly. Called to the South London crime scene, Maeve Kerrigan's first thought is that this is a domestic dispute gone bad. But the husband - found bloody and unconscious in an upstairs room - insists he's the third victim not the killer. However, the only witness is his young daughter. And she's not talking...