Abby and Ellie were never close as children. Now in their thirties, they each harbour deep-rooted resentment for the other -- Abby for her sister's looks and her status as their mother's favourite. Ellie meanwhile is envious of Abby's perfect husband and picturesque home, a villa on the sun-soaked Italian island of Elba. When Abby invites Ellie to stay, both sisters see the break as a chance to relax and put aside their differences. But with their mother Susanna there too, all the simmering tensions of the past quickly rise to the surface. And Ellie suspects that Abby and their mother are keeping a dangerous secret... But after a shocking act, the sisters have only each other to rely on. Vulnerable and scared, trusting each other will be the biggest risk of all...