 When he learns his days are numbered old count Hervé de Kéraudren decides to hide in a secret alcove and to die there, just to annoy his heirs. As a result of his body not being found the latter will have to wait for five years until they can inherit the count s money. Very upsetting indeed, all the more as they are required to keep up the Kéraudren estate in the meantime. To collect money, nephews and nieces organize a Son et Lumière show at the manor while busily looking for the missing corpse. But, unexpectedly, they get killed in turns. Murders or accidents? Jean-Marie, his fiancée Micheline and his cousin Edwige investigate and finally succeed in exposing the culprit. And, the count s body being found by chance, all goes back to normal.