Kira Sakamichi is a career-driven woman, trying to achieve success before her mother's constant interference sentences her to a relationship. But when a grudging drive to meet her mother's latest "selection" ends in a lake accident, Kira wakes up lost in the past, the concubine of a 16th century samurai, and mother to his six-year-old son. When actions in battle lead to the samurai's condemnation, Kira learns that she and her son will share the samurai's fate. Only by understanding the importance of duty and family in both time periods can they survive.