After sixteen-year-old Raina learns that she is a perfect match for donating bone marrow to a leukemia patient in Virginia, she discovers that the young woman is the sister she never knew she had.

With the support of her two best friends, sixteen-year-old Kathleen tries to balance her summer volunteer work at the hospital with her responsibilities caring for her mother, who has multiple sclerosis, and her attraction to a handsome boy.

Reminded of what life was once like by the opening of a first-grade time capsule, seventeen-year-old Alexis now faces the pressures of senior year in high school, her parents' total focus on work, and the recurrence of her twin brother's leukemia.