Yuki Yudzuru, home alone, hears strange noises from the bathroom. Pushing open the door, she finds her mother, Yuma Sano, in a compromising position with their neighbor's son. Yuma, caught red-handed, freezes in shock, her hands still dripping with soap. The bathroom fills with an awkward silence, Yuki's eyes widening in disbelief as she takes in the scene, her mother's secret now exposed.