Meredith Appleton arrives on South Solitary island with her elderly uncle George Wadsworth, who has been sent as the new Head Lighthouse Keeper after the suicide of the last one. He is a gruff, exacting man who treats any disorder with sharp criticism, setting a tense tone for the unfamiliar life that awaits them. Meredith quickly meets Nettie, a local girl, who introduces her to the island’s rough charm and the delicate balance of its community. She also makes the acquaintance of Alma Stanley (the mother) and her two sons, Tom and Robbie, while the father, Harry Stanley, escorts George on an inspection tour. George disapproves of the state of loose animals, the absence of lighthouse keeper Jack Fleet, and a lingering history of lighthouse outages, hinting at deeper troubles that haunt the place.
That night, Meredith is trying to prepare tea when she hears baby birds chirping in the stovepipe and douses the fire, missing the moment to make hot tea for her uncle. The strain of isolation soon reveals itself in other ways: Jack Fleet, the missing lighthouse keeper, suffers a panic attack on his watch, a consequence of wartime trauma that shadows the island. Nettie shows Meredith the unreliable emergency message system using homing pigeons; a routine check to reassure everyone falls apart when the birds return to their coop, rendering the system useless just when it matters most.
In a quiet moment with Alma, Meredith opens up about a painful personal history. She reveals she is unable to bear children; she lost her fiancé in the war, later became pregnant through an affair with a married man, and complications led to the removal of her womb. This confession underscores her sense of vulnerability and explains why the possibility of a permanent home feels so important to her. Meredith’s struggle to connect with South Solitary’s peculiar residents grows more acute as the days pass, and the island’s rhythm intensifies her loneliness. Harry visits her during her bath and crosses a line, seducing her in a moment of misguided longing. Nettie witnesses Meredith and Harry together and tells her mother, who in turn informs George. The family is soon seen leaving the island on the next passing ship, their departure signaling an abrupt end to Meredith’s attempt at building a life there.
Amid the change, George pushes ahead with the supplies, but his exertion proves too much and he suffers a heart attack. He dies, leaving Meredith and Jack to carry the burden of solitary duty in his stead. Jack steps into the role of sole keeper, showing both his competence and a fragile humanity that has been sharpened by war and isolation. The two men bury George and deliver a quiet, heartfelt eulogy that acknowledges the loss and the responsibility now resting on their shoulders. A fierce gale soon arrives, sealing Meredith on the island with Jack for several days. During the storm, Meredith learns how to manage the light and the semaphore system, and she discovers a depth to Jack that she hadn’t anticipated. Their conversations become the lifeline that keeps loneliness at bay, and Meredith expresses a longing for permanence that Jack cannot fulfill in that moment, triggering a wave of panic and… visions of a ship in distress that drive him to flee into the surrounding wilderness.
As Meredith carries on with the duties around the lighthouse, she finds her lost lamb with Jack’s help, a small symbol of return and responsibility that helps anchor her. A distant ship appears on the horizon, and Jack signals for it to pick up Meredith, who pleads to stay but understands the strain of companionship on his nerves. He declines, overwhelmed by the prospect of close company, yet their connection remains electric. They share a kiss before parting, vowing to keep in touch, with Jack promising to visit on leave. The final image lingers on Meredith watching him from the water, then catching sight of the semaphore message he has displayed. A smile crosses her face as she slowly moves away from South Solitary, carrying the memory of their bond as the island fades behind her.
