One unremarkable afternoon, Rosie watched her daughter Saoirse cycle into town, expecting to hear the slam of the door when she returned a few hours later. But the slam never came.

Eight years on, after an extensive investigation into her disappearance, Rosie is the only person who stubbornly believes that her child might still be alive. When Rosie receives a call from her father, asking her to return home for the summer, she is forced out of her limbo.

Life on the island of Roaring Bay revives old rivalries, but it also brings new friendships and unexpected solace.

Yet, when a sudden glimmer of hope appears, Rosie is forced to face an impossible question: is she right to think that Saoirse is still alive? Or will her belief that her daughter will one day return to her come at the cost of everything she has left?