A body is found in a park which appears to have been mauled to death by a dog. Dr Graf however confuses the situation when he tells Alex that the autopsy reveals that the death was caused by a wolf, which has been extinct for over 200 years.

Edi Salzer, a homeless man, is found murdered. In order to solve the case Alex and Rex go undercover to mingle with the homeless. The autopsy reveals that Edi was killed by nerve gas and time is running out for them to solve the case.