Valentina Cavalli is a key witness in a conspiracy trial against a bank. On the day she is due to appear in court to testify, a gas explosion occurs in the flat next door to hers. The gas mains have been tampered with and it's obvious that someone wants her dead. But who is behind the attack? Inspector Rivera and Rex investigate.

Inspector Rivera and Rex receive a strange visit from a war widow, who claims the ghost of her dead husband is responsible for the murder of a man and the bashing of another. The 'ghost' however is more - and less - than it appears to be.