Delfi Mauro

Patients and those working in an isolated mental hospitals are murdered, one by one, by a madman lurking in the corridors

The elderly O'Hara, owner of a fortune in emeralds, offers half of his estate to whoever manages to get him out of jail. The adventurer Don Casey arrives in the town of Guaynas, ruled by the tyrant Villarde, to fulfill that wish.

When a scientist and his death ray are taken by a group of enemy agents, secret agent Bart Fargo is sent to retrieve the death ray and save the scientist.