Captain Olmedo, an high-ranking officer in charge of dismantling the city's military headquarters, is found dead in his house - shot through the chest by a bullet from his own gun. His daughter Marina does not believe the official verdict of suicide and hires Cupido, a peaceful private detective, to investigate. As always, Fuentes paints a sociological portrait of present-day Spain while at the same time exploring the secret reasons that may push an individual to commit murder.