Satoshi Ando is University psychology professor who raised his daughter Kana on his own since the death of his wife many years earlier. One day, Kana dies by falling from the balcony of her high school and it remains unclear whether the incident was an accident or suicide. Ando is overcome with despair and feels guilty that, as a psychology expert, he didn’t recognize any warning signs. Wanting to believe his daughter’s death was an accident, he contacts one of Kana’s high school friends to find out more.