Hans Kuperus lives in an orderly household with his wife and maid in a small Dutch town. Every month, he attends a doctors' meeting - he only skips it twice. The first time is to confirm that his wife is indeed cheating on him, as an anonymous letter claims. The second time, he shoots the two of them and disposes of the bodies in the canal. No one suspects him, and his life continues as usual. But then Kuperus learns who the sender of the letter was. And as the ice melts, the canal reveals the two bodies.