Kaho, a normal office worker, was looking forward to her engagement with her lover, Ryota. However, Kaho's normal life takes a sudden turn after Ryota's mother is hospitalized because of an accident. Contrary to her gentle appearance, the mother casts a disturbing gaze towards Kaho... Hidden there was a suspicious relationship that transcended the normal affection between a parent and their child. While she was starting to feel uneasy about Ryota's actions, Kaho consults his father, Tetsuya, and slowly becomes attached to him...