 Arno Kulm, an internationally successful actor, is privately rather a shy person, not least because of his psychologically unstable wife Inge, who cannot endure his success. Kulm regularly seeks the support and advice of his friend Dr. Winter, his agent and confidant of many years  standing. Kulm trusts his friend so implicitly that he has even appointed him administrator of the huge personal fortune that Kulm s wife has brought into the marriage. Winter, however, is involved in several shady dealings. He is only feigning friendliness, and is exploiting Kulm for his own ends. Together with his mistress Sylvie, an unscrupulous French journalist, he plans to make the ageing actor s fortune his own. Kulm fell head over heels in love with Sylvie during a TV report, and Dr. Winter and Sylvie plan to exploit this for their own ends. Winter hatches an evil plan: should Kulm s wife be "successful" in carrying out one of her many suicide attempts, Sylvie will seduce Kulm into marrying her and then divorce him one year later. Winter will then use legal means to secure a substantial settlement for his mistress as well as for himself. What Winter doesn t tell Sylvie is that he is planning to speed things up: he drowns Kulm s wife in her bath and then makes the murder look like suicide. The first obstacle between Dr. Winter and his future wealth is thus overcome. It is only a matter of weeks before Kulm makes Sylvie a marriage proposal, and the latter happily accepts. But very soon after the marriage Winter, whose financial situation is growing increasingly precarious, decides that he can t wait until the divorce. He resolves to rid himself of Kulm once and for all - without Sylvie s knowledge - by means of a cleverly arranged accident. Kulm s death would mean that Sylvie, his mistress, would inherit the entire fortune. Why wait for a small settlement, with all of it there for the taking? Kulm s new wife is careless, though, and her husband starts getting suspicious. That night he follows Winter and Sylvie to their love-nest. He has no idea that in doing so he has narrowly avoided being murdered by his so-called "best friend". Now Kulm s suspicions that his wife is betraying him are confirmed. He is utterly shattered. Moreover, on arriving home the actor realises that Winter had been planning to murder him, and to make his death look like smoke poisoning. Kulm decides to avenge himself on his wife and her lover. Outwardly, though, he continues to play the role of the unsuspecting husband. Now that their first murder attempt has failed, Winter and Sylvie hatch a new plan. This time they decide to get Kulm out of the way by staging a car accident. Sylvie s greed for her husband s fortune outweighs her few remaining scruples. Kulm is on his guard, however. He cleverly avoids their attempts to anaesthetize him, and then feigns unconsciousness very convincingly. Just as Winter is on the point of placing Kulm s limp body behind the wheel of the car, Kulm "comes back to life". His former friend tries to run away, but Kulm guns him down in cold blood. Kulm ends this thriller with a real coup de théâtre - he s not an experienced actor for nothing. He successfully manages to shift the blame for Winter s murder on to Sylvie, who is unable to exonerate herself without revealing her true intentions at the same time. Pitilessly Kulm looks on as Sylvie - for whom he would have laid down his life only a short while previously - is condemned to life imprisonment.