Everyone in the Istanbul neighborhood of Moda knows the Devil's House, a crumbling Ottoman mansion that was once the home of a princess. Her four children are still there, living on different floors and never speaking to one another. After each of them is stabbed in the heart, Inspector Ikmen digs into their past and it becomes clear they have been harboring a secret. In this 19th outing (after On the Bone), a young couple are arrested for a series of random killings on the streets of Istanbul. They claim to have been squatting in the Devil's House, but Inspector Ikmen must probe the darkest depths of this ancient city to find the full answer.