Machi Onodera, a 27-year-old teacher, is focused on finding a perfect match for marriage. Her world is upended when Yuto, the younger brother of her high school first love Yuichi, transfers to her class, resembling Yuichi in his youth. Torn between the charming Yuto and a chance reunion with Yuichi, Machi navigates a thrilling love triangle, caught between passion and nostalgia.