You never know what's going on behind closed doors ... If you passed it on the street, you'd see an ordinary London townhouse. You might wonder about the people who live there, assume they're just like you. But inside a family is trapped in a nightmare. In the kitchen, a man lies dead on the blood-soaked floor. Soon the police will come, and they'll want answers. Perhaps they'll believe the family's version of events - that this man is a murderer who deserved to die. But would that be the truth?