A Second Chance by Walt Mussell

Her only future lay in her death...in the past 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, part of the household of a 16th century samurai, and mother of a six-year-old son. When actions in battle lead to the samurai's condemnation, Kira learns that the house will share the samurai's fate. Only by understanding duty and family in both time periods can they survive.