From Rotterdam, Gerhard Bern has received the terrible news that, for no ostensible reason, his brother has committed suicide. The only clue seems to be his membership of a secret club. To find an explanation, Gerhard, accompanied by a detective, hurries to Rotterdam, where he is given accommodation by Consul Verstraaten, a friend of his father. There he meets and falls in love with the Consul’s daughter Ilse and shortly thereafter they become engaged. In the meantime another mysterious suicide has been reported. It appears that in both cases the men, both members of the same club, had taken out a life insurance policy and that a certain Mr van Gelderen, leader of the club, has collected the insurance money.