The Devil's House, a crumbling Ottoman mansion once the home of a princess, is a place associated with ill fortune. The princess's four children, now in old age, still live there in separate apartments and when one is found stabbed through the heart, it is discovered that the other three siblings have met an identical fate. As Inspector Ikmen digs into their past he discovers they have been harbouring a secret. Meanwhile a young couple are arrested for a series of murders on the streets of Istanbul. They claim to have been squatting in the Devil's House. But this fiendish mystery is far from over and it will take Inspector Ikmen to the darkest, most devilish depths of this ancient city.