Yuu was in the arms of her mother's lover, a detective named Kawamura, but when her mother found out about their relationship, she ran away from home. Five years later, when Yu returned to Yokohama, her mother had committed suicide with a thug, and her half-sister Louis views Yu as his enemy. Yu learns that Kawamura, who quit his job as a detective and became a yakuza member, is involved in his mother's death.
