This book tells the story of a fisherman. Santiago, an old Cuban fisherman, finally caught a big marlin by himself after 84 consecutive days without catching a fish, but the fish was so big that he was exhausted after dragging his boat at sea for three days and was killed by him Dead tied to the side of the boat. On the way back, he was attacked by a shark again, and when he finally returned to port, only the head, tail and a backbone were left. In the days when old San Diego went to sea, his long-term friend had been waiting loyally by the seaside, welcoming his return with confidence.