On the Beach Summary

After a nuclear conflict devastates the Northern Hemisphere, the resulting radioactive fallout threatens to extinguish all life, gradually moving towards southern Australia within the year. Lieutenant Commander Peter Holmes of the Australian Navy, based in Melbourne, is assigned as liaison to the U.S.S. Scorpion, an American nuclear submarine under the command of Commander Dwight Towers. Despite his concern for his wife, Mary, and their infant, Jennifer, who will bear the brunt of the radiation fallout in just six months, Peter accepts the position. He introduces Dwight to Moira Davidson, a young woman who drowns her sorrows in alcohol, grieving the loss of a future she will never realize due to the impending catastrophe. Dwight, despite being aware of the demise of his family in America, continues to regard them as alive, anticipating his return home.

John Osborne, a civilian scientist, soon joins the Scorpion's crew. The submarine embarks on an eleven-day journey along the Australian coast in a futile search for signs of life, their only encounter being a lone dog. The crew hypothesizes about the root cause of the war, with no real understanding of how it escalated. Once back, they report their fruitless journey, and the concern of an outbreak of measles in the crew raises fears for baby Jennifer's health. Meanwhile, Dwight and Moira's friendship deepens, though Dwight remains faithful to his memory of his wife. Both Peter and Mary, and Moira's father, continue to make plans for a future they know will not exist.

Assigned to explore the Jorgensen effect, a theory proposing that snow and rain might cleanse the radiation from the atmosphere, Dwight and Peter are also tasked with investigating a mysterious intermittent radio signal originating from Seattle. Before leaving, Peter warns Mary of the potential radiation sickness that might affect her and Jennifer, suggesting a mercy killing to spare their daughter a slow, painful death. While Dwight is away, Moira embarks on secretarial courses and moderates her drinking. The expedition to the west coast of the U.S. reveals the source of the hopeful signal - a broken windowpane pressing against a transmitting button in the wind. The radiation finally reaches Melbourne in August. The city's inhabitants embrace their final days doing what they truly desire. A fatal motor race, gardening, fishing, and spending time with loved ones fill these final moments until, one by one, they succumb to the inevitable radiation sickness or take the desperate step of suicide. The finale sees Moira watching from a cliffside as Dwight performs his last duty, sinking the Scorpion and dying with his ship. Alone, she takes her final pill, accompanying it with a swig of brandy.