Maya and Rebecca Ward are both accomplished physicians, but that's where the sisters' similarities end. As teenagers, they witnessed their parents' murder, but it was Rebecca who saved Maya from becoming another of the gunman's victims. The tragedy left Maya cautious and timid, settling for a sedate medical practice with her husband, Adam, while Rebecca became the risk taker.

After a devastating hurricane hits the coast of North Carolina, Rebecca and Adam urge Maya to join them in the relief effort. To please her husband, Maya finally agrees. She loses herself in the care and transport of victims, but when her helicopter crashes into raging floodwaters, there appear to be no survivors.

Forced to accept Maya is gone, Rebecca and Adam turn to one another—first for comfort, then in passion—unaware that, miles from civilization, Maya is injured and trapped with strangers she's not certain she can trust. Away from the sister who has always been there to save her, now Maya must find the courage to save herself—unaware that the life she knew has changed forever.