A woman robs a bank. A corpse is found shot through the heart in a room locked from within--no firearm in sight. To the eerily intuitive Inspector Martin Beck, these seemingly disparate cases are facets of the same puzzle, and solving it is of vital importance. Only by finding our what happened in the locked room can Beck--haunted by a near-fatal bullet wound and the demise of a soulless marriage--escape from an airtight prison of his own.