Once the tide turns, you can't hold it back. When Evie's father falls desperately ill, she finally returns to the family home on Orkney and the wild landscape she left as a teenager, swearing never to return. Not everyone is happy at her arrival, particularly her estranged sister Liv, their relationship broken after a childhood trauma. As Evie clears out her father's neglected house to prepare it for sale, lonely Evie finds herself drawn to a group of cold-water swimmers led by her old friend Freya, who find calmness beneath the waves. Together they help Evie face up to the mistakes in her past, unlocking a treasure of truths that will reverberate through the community, and shake her family to its core.