When a girl answers a cry for help, she finds a man locked in the boot of his car along with his wife, who's been stabbed to death with a Serbian army knife. Inspector Rivera and Rex are called to investigate and focus their attention on the knife and a possible connection to the Serbian army.

A politician speaking at a rally in support of tough laws to constrain the power of the banks is shot. The supposed assassin, an Arab, is quickly located by a bodyguard and also shot dead. Forensic evidence, however, points elsewhere, and when the bodyguard himself is killed, Inspector Rivera grows more certain of a conspiracy involving top politicians and bankers.