An aging couple, Ethel and Norman Thayer, continue a tradition of spending each summer at their cottage on a lake called Golden Pond, in the far reaches of northern New England. When they first arrive, Ethel notices the loons calling on the lake "welcoming them home"; Norman, however, claims he does not hear anything. As they resettle into their summer home, Norman, who is about to turn 80, shows signs of dementia when he is unable to recognize several family photographs. He copes with his memory problems by frequently talking about death and growing old. Ethel does her best to liven up the atmosphere – they play Parcheesi, admire the natural scenery, and talk to the mailman, Charlie, who delivers mail and visits via boat. They are visited by their only child, daughter Chelsea, who is somewhat estranged from her father. She introduces her parents to her fiancé Bill and his 13-year-old son, Billy. Norman tries to play mind games with Bill, an apparent pastime of his. Bill tells him he knows what Norman is doing and he doesn't really mind, but that he will take only so much of it. In another conversation, Chelsea discusses with Ethel her frustration over her relationship with her father, feeling that although she lives thousands of miles away in Los Angeles, she still feels like she is answering to him. Before they depart for a European vacation, Chelsea and Bill ask the Thayers to allow Billy to stay with them for a month while they have some time to themselves. Although Norman is acting cynically as his 80th birthday approaches, showing signs of dementia and having heart palpitations, he allows Billy to stay. Billy is at first annoyed by being left with elderly strangers, with no friends nearby and nothing to do. He resents Norman's brusque manner, but eventually comes to enjoy their Golden Pond fishing adventures together. Billy also begins to enjoy reading books in the cottage, first reading Treasure Island and later A Tale of Two Cities. Billy and Norman soon grow obsessed with catching Norman's fish rival, "Walter", which leads to the accidental destruction of the Thayers' motorboat in a rocky area called Purgatory Cove. Norman gets thrown overboard and suffers a head wound, and Billy dives in the water to save the old man. They are later rescued by Ethel and Charlie. Once healed, Norman goes fishing with Billy and they finally catch "Walter", but they eventually release the fish. Chelsea returns to learn her father has made friends with her fiancé's—now husband's—son. When she sees the change in her father's demeanor, Chelsea attempts something Billy accomplished that she never could: a backflip. She successfully executes the dive in front of a cheering Norman, Billy and Ethel. Chelsea and Norman finally fully embrace before she departs with Billy. The final day on Golden Pond comes and the Thayers are loading the last of the boxes. Norman tries to move a heavy box but starts having heart pain and collapses onto the floor of the porch. Ethel tries unsuccessfully to get the operator to phone the hospital, and goes to comfort her husband. After being given nitroglycerin by Ethel, Norman says the pain is gone and attempts to stand to say a final farewell to the lake. Ethel helps Norman to the edge, where they see the loons, and Norman says they are calling on the lake, "saying goodbye". He notes how they are just like him and Ethel; that their offspring is grown and gone off on her own, and now it is just the two of them.