This ship is called ‘Achilles’, and it has always been a ship that sailors yearn for for many years. Its excellence is not only in the performance of the ship itself, but its captain is an admirable man. Everything went smoothly until a passenger released the news that he had hidden the world-famous treasure, the Horn of Winter Plum, somewhere on the ship. Treasure hunters from all over the world flocked to each other, searching for it again and again, and finally all came back in despair. When everyone thought the matter was over, the crisis came quietly... An unexplained riot broke out on the ship, and the captain led the sailors to rise up to resist, and eventually both sides died together—this is the result of some speculation, because Achilles Since then, he has been lost in the sea. Round-faced Doudou received the tangible news: The Horn of Samuel never left Achilles, and the ship is currently anchored on the coast. He entrusted Kitaichi to board the ship to find it, and promised that he would get a large reward if he found the treasure. Except for the Horn of Winter Plum, there are many hidden treasures on this ship. It will never come back empty-handed, it's just a matter of how much money it takes. Kitaichi, who received this promise, agreed to the round-faced Peas without thinking more. The exploration begins here...