Sure this entertaining little flick never wrote movie history and won't ever do. On a camp and exploitation level however it scores very fine. Forget about the story, it's the bearded 'dangerous secret formula' stuff, spiced with plenty of 'mysterious' cases of murder and a row of usual suspects and red herrings. Like all flicks of the infamous German "Edgar Wallace" circle (this one being an entry based upon a pulp novel by Louis Weinert-Wilton) it provides cheap thrills in a usually foggy London Town, featuring clichés such as the smart knows-it-all Scotland Yard inspector (sure with bowler hat, pipe & umbrella), the even smarter and more dynamic private eye or secret agent, the mysterious night club by the Thames or in a dark Piccadilly sidestreet. Right here's where you find the center of all evil proceedings, the "Chinese Carnation" inn, run by a wicked but sexy eurasian lady. She is introduced with a cheesecake shot of her high-heeled legs, lying on her divan, seductively scored with an itchy hammond organ sound. That hammond sound will accompany us and provide relentless cheesiness throughout the whole movie. But don't get it wrong: this is tacky fun and highly entertaining, mainly due to the unique pairing of the three great icons of Euro exploitation cinema of the 1960s: Brad Harris, Klaus Kinski and Horst Frank. Recommended - if only for fans.