The Fellowship of the Frog(Edgar Wallace - Der Frosch mit der Maske)

Both Scotland Yard and an amateur American sleuth are tracking a master criminal known as The Frog, identified both by his bulging-eyed mask and the frog icons branded onto the forearms of his henchmen. The trail leads them to the manor of an enigmatic man whose lovely daughter captures the fancy of both the American playboy and the villain himself.