In the morning, Thomas Hudson discovers that Eddy had stayed up all night splicing fishing lines. The moon had been full, which bothered both of them. On the trip out to sea, Tom confesses to his father that his friendships with grown men have ruined his opinion of boys his own age.

Also in the morning, David manages to catch a broadbill, a type of swordfish, but the size of the fish means it is not going to be an easy catch. They move the boat out to make it easier to bring the fish in. David vows to hang on to the fish until death. His father and brothers are seriously concerned about this possible outcome. Tom especially is worried, but he confesses that he is the family worrier. Roger tries to keep David cool by pouring water on him.

The fish continues to stay deep underwater, and David maintains his hold on him. Tom is impressed because David does not do well in sports. David begins to pull the broadbill in, inch by inch. He snaps at Andrew, who feels bad that he interfered. At last the big fish comes up to the surface. Thomas Hudson backs up the boat, following the fish. Eddy estimates that the fish weighs a thousand pounds. As the fish circles, Thomas Hudson maneuvers the boat to keep it astern. In his nervousness, Tom begins talking, praising David. The boat is moved to put David in the shade.

After two hours, David continues to wrestle the fish, which is circling beneath the boat. After three hours, there is no progress. The fish dives deeper, and Thomas Hudson suspects he is going down to die, which would ruin David. David is on his knees, desperately holding on to the fish; Andrew is holding onto his feet. David is almost out of line. Eddy pulls David back into the chair, holding him around the waist. Tom notices that David’s feet are bleeding from friction against the deck, and his hands are masses of open blisters. Tom worries even more, but Thomas Hudson insists that David be allowed to finish his fight. Eddy is not as concerned about David’s hands and feet as he is about his head. Roger offers to take over, but David insists on hanging on.

After five hours, David begins to make progress once again, pulling the line in. Thomas Hudson sees the blood on his son’s hands and feet. Slowly the fish is being pulled to the surface. Roger leans over to hook the fish and pull it on board, but he loses it. The fish swims down to the depths, lost forever. David is carried below to the bunk, where his injuries are treated. David says at one point he could not distinguish between himself and the fish. He is glad now that both he and the fish are all right. They are not enemies.