Alexander the Great might well be on his way to conquering the world, but when he decides to explore underwater in a glass-windowed wooden barrel, he enrages Poseidon. The other gods may debate Alexander's fate and make their deals on Olympus but the ocean deity is determined to frighten the young King out of the watery realm. Will Poseidon defeat Alexander and prevent future deep-sea exploration by mortals, or can a single clever Macedonian outwit a god?