At thirty years old, Kyousuke finds himself a NEET, having neither a job nor a clear direction in life. His situation reaches a breaking point when his parents evict him from their home, leaving him with nowhere to go. In this moment of crisis, his closest friend, Rui, proposes an unexpected solution: they should get married, with the explicit intention of divorcing later. The two, who have been strictly just friends for nearly a decade, decide to enter into this contract marriage of convenience. Kyousuke is a romantic at heart, while Rui is a pragmatic young woman, making them a pair seemingly unsuited for a real marriage. Their arrangement is given a specific timeframe of one hundred days living together, at the end of which they plan to part ways. The narrative follows this mismatched pair as they navigate their fake marital life, exploring what they will discover about each other and themselves after their hundred days together are up.