Joan has always done the right thing, both as a palliative care doctor and as a caregiver for her widowed mother, Sheila. Joan's adventurous sister, Vivien, is a different story. She left home as soon as she was able running from an insecure childhood troubled by an alcoholic father and a mother who constantly threw away all their possessions in order to buy new ones. Vivien's rarely been back, working as a nurse in the world's trouble zones, leaving the heavy burden of family on her sister. Still, when Vivien learns that their mother is seriously ill, she reaches out to Joan. She's heading for a remote village where Ebola is spreading, and she's afraid she may die. If she does, she wants Joan to pose as her online so her dying mother won t have to grieve a daughter. It's a lie, but it's the good kind of lie, designed to spare their mother, and so Joan reluctantly agrees, figuring it will never come to that. But Vivien does die. And even as Joan mourns her sister, she begins to impersonate her online, as promised. It's difficult at first, but to her surprise, posing as Vivien becomes liberating, even addictive. Then she receives a message on her sister's Facebook from a man claiming to be the son Vivien gave up for adoption, and the line between right and wrong, adventure and tragedy, really begins to blur.