An Australian woman arrives in London to search for her sister who she finds is involved with a heroin smuggling gang. The gang itself is under attack from an unknown rival, who is methodically assassinating them with a shot to the head.

Uschi Glas
as Danny Fergusson

Hansjörg Felmy
as Inspector Craig

Werner Peters
as William Baxter

Harry Riebauer
as Milton S. Farnborough

Siegfried Schürenberg
as Sir John

Günther Stoll
as Doctor Ellis

Petra Schürmann
as Susan

Friedrich Schoenfelder
as Anthony Wyman

Lyvia Bauer
as Myrna Fergusson

Peter Neusser
as Sergeant Simpson