To celebrate Christmas, the elderly millionaire Simeon Lee—at last—decided to gather all his numerous relatives. But the holiday was unexpectedly cut short by the crash of furniture, followed by a terrible scream. The household rushed to the noise and found the head of the family lying in a pool of blood in the middle of his office. At the scene, inspector Sugdun was called, and, by a lucky coincidence, the incomparable detective Hercule Poirot was staying as a guest with him at the time. Naturally, he also came to the Lee house, where he discovered an atmosphere of general suspicion. The millionaire could have been killed by anyone—because the whole family secretly hated this family tyrant. There are many clues, but none of them points to any of the people present. This is what a real case for the "grey cells" of the great Belgian looks like…