A happily married couple's life is disrupted when the husband's mother suddenly passes away, leaving them to face the dilemma of what to do with their shared two-family home. Just then, the husband's estranged father—who didn't even attend the funeral—returns and moves into the house. As the father-in-law and daughter-in-law, Hikaru Natsuki, are forced to live under the same roof, constant encounters spark tension and friction. Their awkward interactions begin to strain the couple's relationship. Amidst the crumbling household balance, misunderstandings and suppressed emotions gradually give rise to forbidden feelings between Hikaru and her stepfather. The story unfolds as each character confronts their shifting emotions in this delicate family crisis.