In the quiet confines of an inn on the southern edge of the Izu Peninsula, Tomoko Ikuta finds solace from the oppressive summer heat by dozing off in her room. Meanwhile, her children, Keiko, Kiyoo, and Katsuo, are left to enjoy the beach under the watchful eye of their aunt, Yasue. The peaceful afternoon takes a tragic turn as an undertow sweeps Keiko and Kiyoo away, with Yasue unable to save them due to an unexpected heart attack.

The Illusory Calm

Tomoko's nap is disturbed by the alarming news of Yasue's collapse. Rushing outside, she sees a man desperately performing artificial respiration on her sister-in-law. Katsuo, thankfully safe, is cradled by a fisherman, yet the whereabouts of the other children remain unknown. Hours drag on, and it is only when the doctor concedes defeat in reviving Yasue that the grim reality unfolds — Keiko and Kiyoo have drowned. As night descends, local men begin the heart-wrenching search for the children's bodies, and Tomoko sends a telegram to her husband, Masaru, conveying the devastating events.

Confronting Grief

Masaru rushes from Tokyo to the inn, where he and Tomoko perform their expected roles in the aftermath of tragedy. Tomoko, filled with self-blame, kneels before her husband, while Masaru offers her understanding. Soon, the bodies of their children are found, and both parents struggle with a torrent of grief. Tomoko secretly resents her husband’s mourning over Yasue, feeling it somehow lessens his sorrow for their children. Despite her inner turmoil, she adheres to social conventions when Masaru’s parents arrive for the funerals, taking responsibility once more and apologizing to them. Yet, in private, she vents to her own parents about the palpable accusations against her, questioning why no one seems to acknowledge her profound loss.

Lingering Fear and Adjustment

Following the calamity, Tomoko is plagued by the fear of further accidents. A recent car mishap involving Masaru exacerbates her anxiety, particularly when traveling with Katsuo. Her caution extends to everyday activities as she insists on carrying boiled water for him rather than allowing him to drink from public fountains. Small moments catch her off-guard, like when she instinctively considers buying gifts for Keiko and Kiyoo, forgetting momentarily they are gone. To cope, she throws herself into attending plays and concerts, and later, sewing becomes a refuge, allowing her to escape the haunting memories.

A New Beginning

Winter brings news of a new pregnancy, and with it, Tomoko feels a natural sense of forgetfulness envelop her. Both she and Masaru begin to see the tragic summer as a distant event, transforming into spectators of their own past. The incident gradually fades into a generalized lesson about vigilance on the beach. The birth of their daughter, Momoko, seems to close that painful chapter. Yet, as Momoko turns one, Tomoko expresses a desire to return to the Izu Peninsula beach. The family stands together on the shore, where Masaru notices a familiar expression on Tomoko's face as she gazes out at the sea, silently waiting for her lost children to come back.