The plot follows (Shinoda), a recently married woman who manages a small apartment building with her husband. Their quiet life is disrupted when her estranged former stepson, Ryo , moves into the unit next door. Years earlier, Ryo had confessed his feelings to her before an abrupt separation. Now forced into close quarters, the buried tension between them reignites. The story uses the classic "forbidden proximity" trope: Natsuki’s husband works late shifts, leaving her alone in the shared laundry room and thin-walled corridors. A rainy night, a forgotten key, and an accidental encounter in his room lead to a violation of trust that Natsuki vows to take to her grave.
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