A gripping mystery delving in to the clashing emotions of two mothers whose ideal family image is suddenly shattered.

Izumi Mizuno’s uneventful life as an ordinary housewife drastically ends when her son, junior-highschool student Taiki, is mistaken for a suspect in a serial murder case for acting suspiciously late at night. When the police tries to question him, he flees on his bicycle, crashes into a parked truck and tragically dies. What was Taiki up to the night he snuck out of the house and rode away on his bicycle?

Fifteen years later, a young woman is stabbed in her apartment in Tokyo. The man she was cheating with, Tatsuhiko Momoi, a company employee, goes missing, so the police consider him a key witness. Frustrated by his wife’s indifference, Tatsuhiko’s mother, Chie, desperately tries to find him.

As detectives Mitsuya and Tadokoro proceed with their investigation, it soon becomes clear that the two mothers’ feelings for their sons are intertwined and the shocking truth that links the two seemingly unrelated cases comes to light. Prolific mystery writer Toshika Masaki investigates one of the most difficult relationships in the world, the one between a parent and a child.