Who is the accomplice of the pirates who captured the ship on which Michel and his cousin Daniel went on a journey? The radio operator who slipped the guys strong sleeping pills instead of seasickness pills? Or the captain's assistant, for some reason refusing to take decisive action? However, whoever he is, first of all it is necessary to free the crew languishing in captivity and let them know ashore. But how to do this when the forces are so unequal? And then Daniel disappears without a trace, and Michel finds himself face to face with the criminals...

The story was also published under the title “The Secret of the Asleep Sailors.”