Katy Henry is lost and lonely. A single mother, plagued by fatigue and anxiety, she rarely has time for friends. But when she encounters Sibeal Matthews, all this changes. Sibeal is everything that Katy is not: assured, headstrong and charming. Katy soon finds herself pulled out of her isolation into a fierce friendship. But Sibeal is not all that she seems. Tragedy haunts her, and for all her feistiness, she is startlingly dependent on her brother, Gabriel. And when her life begins to spectacularly unravel, Katy is swept up in the storm. As Katy fights to protect herself and her son, it's not just Sibeal who threatens to endanger them - Katy's own past starts to rupture. Who can Katy trust? Can she even trust herself?