Something is gravely wrong with the crew of the Rita Anne. They have stopped speaking and they seem to walk the decks stooped over. At night, shrieks can be heard coming from the forward hold.

Why this dreadful and dangerous change? Could it have anything to do with the huge, glowing rock that was found the week before? Perhaps it should not have been brought aboard the ship. What is this extraordinary rock — what wretched power does it hold? And how on earth will the captain be able to save himself and his feverish crew?