 A woman has jumped or been pushed from five stories of an apartment house. The detective (Umberto Spadaro) on the case lives there, and he discovers that the woman s estranged husband does also. She had been extorting money from him and had threatened to kill herself if he didn t pay. The detective s daughter (Delia Scala) is in love with the husband and tries to provide an alibi for him. But when a genuine alibi is proved, circumstances point to the (innocent) daughter as the killer.