An aging fisherman, who has gone 84 days without catching a fish, sets out alone into the Gulf Stream, determined to end his unlucky streak. He is guided by years of experience and a deep connection to the sea. His young apprentice, who is forced to fish with more successful fishermen, deeply admires him, wishing for his luck to change. Solitude at sea allows the old man to reflect on his life, struggles, and dreams. On the 85th day, he finally hooks a massive marlin, initiating an epic battle of endurance between the old man and the sea creature. The struggle becomes a test of the fisherman's resolve and strength as he fights against fatigue and pain.

Wielding nothing but a thin line and his time-honed skills, the old man wrestles with the marlin for days, gaining respect for the powerful fish. His determination and unwavering spirit become evident as he confronts both the physical challenges of the sea and the mental challenges within himself. Alone amid the vast ocean, he speaks to the marlin, recognizing it as a worthy adversary and forming a bond of mutual respect. With his fate tied to the marlin's, the old man's journey becomes a profound exploration of personal redemption, identity, and the relentless pursuit of a dream against insurmountable odds.