Skiff's mother left him three directions before she died - think smart, speak true, and never give up. Skiff is trying to live up to her expectations but finds himself acting alone since his father is deep in grief. When their boat is damaged beyond use by the rich bully in town Skiff doesn't see any way to dig out of the problems he has. But when Skiff sees a man selling a giant tuna in town for a huge sum of money he decides that he will catch a fish at least that big to solve his problems. Since their main boat is out of service Skiff will have to get the big fish using just his ten foot boat and a harpoon made by his father. He sails before dawn one day to a spot 30 miles out into the ocean to wait for his dream fish. But when problem after problem threaten his dream, he thinks that he has probably ignored his mother's rule of thinking smart and it might even cost him his life.