Diving Helmet Boy A boy who likes to wear an old diving helmet. He lives with his fisherman dad who has to be away on the ship many days each time he works.

The boy has a dream to get on a boat and catch Makuro (Tuna) with his dad when he grows up.

However, his dream can’t never come true. One day, the boat that his dad sailed into open water has encountered the big storm and sunk.