High school sophomore Miki Koishikawa's world is flipped upside down when her parents announce they are divorcing to swap partners with a couple they met in Hawaii—and ask for her blessing. At dinner, she meets the other family's son, Yuu Matsura, who starts as a condescending tease but reveals a more appealing side over time. As Miki adjusts to the unconventional household, she begins to fall for him—though the game also lets players steer her heart toward her best friend Ginta or her coworker Kei instead.