An aging Cuban fisherman struggles with a giant marlin far out in the Gulf Stream, isolated from the world and from human help. For days, he fights the marlin alone, admiring its strength, dignity, and faithfulness to its identity—its destiny is as true as his as a fisherman. He finally kills the marlin, but sharks attack and devour it before he can return to the shore. The fisherman returns home empty-handed but remains undefeated, having proven his abilities to himself.

This novel tells the story of a group of Caribbean turtle fishermen who set out on a dangerous journey to the remote island of Far Tortuga. The narrative unfolds through the use of dialect, sea charts, and poetry, creating a vivid and unique portrayal of the men's struggle for survival against the harsh realities of the sea. As the crew faces various challenges, their story explores themes of man's relationship with nature, the passage of time, and the inevitability of death.

Set in the early 19th century, the narrative follows the adventures of a young British naval officer as he sails the Caribbean aboard the schooner Midge. Engaging in naval warfare, the protagonist confronts the perils of the sea, piracy, and the complexities of colonial life. His journey is marked by personal growth, friendships, and the harsh realities of maritime conflict during a tumultuous period in history. The book offers a vivid portrayal of naval life, combining action-packed sequences with a detailed depiction of the era's naval strategies and shipboard existence.