The old man Santiago has fished in the Golf Stream for eighty-four days without catching a single fish. In the first forty days, the boy Manolin has been with him. But after forty days of fruitless search for fish, the boy's parents decide that the old man is unlucky. They, therefore ask the boy to withdraw from the enterprise. On the orders of his parents, Manolin joins another boat on a fishing trip which catches three great fish in the first week.
The old man labours day after day with the same ill luck. But he loves the sea and fishing and so persists in spite of repeated failure. One morning Santiago determines to break this cycle of failure and turn defeat into victory. He therefore sails far out to sea, equipped with sardines and two baits wrapped in a newspaper. The old man works hard and long. Eventually he catches a big fish. In his loneliness Santiago has a bird for company.
Santiago knows it is a big fish because of its weight. The old man moves with the fish for a number of days. He loses sight of the coastal landscape but he feels at home in his boat on the wide expanse of the ocean. The old man experiences intense pain of endurance with a cramped hand before the fish is caught. The old man feels exhausted. He has little food, feeds on raw fish, and has quite scant sleep at night.
The old man is surprised at the enormous size of the fish. Killing the fish is very tasking and strenuous work, but fastening the huge fish to his boat presents a very challenging task. The old man is happy at the turn of events. He makes calculations of the monetary worth of the fish. "He is my fortune", he thinks. He cannot believe the size of his fish. His mental calculation pegs the weight of the fish at fifteen hundred pounds, maybe more. It would bring the highest price on the market, which is enough to compensate for all the toil and ill luck of former times and trips.
Fortunately, the winds rise and begging to drive the boat towards the coast. He is homeward bound with a successful catch. But the old man has not reckoned with the sharks which begin to eat the fish. He kills several of them but they came in a pack. He fights hard and bravely, but the sharks are one too many. Besides, he has no weapon to fight with. "Nothing", he says aloud, "I went too far". By the time he reaches the shore, there is nothing left of the huge fish which measures 'eighteen feet from the nose to tail'. The old man is completely exhausted physically. The big fish which is to have brought in a large amount of money is now a mere skeleton to be taken away by the tide.
In spite of his apparent failure to retain his catch, it is worth noting his indomitable courage hugely displayed in his fight against the sharks. The sea defeats him; he is physically broken, but there is much virtue in him having fought hard against tremendous odds.