Capucine feels like a fish out of water. For her exuberant mother Solange and the rest of her extended family, her shyness is an inexcusable flaw. As her graduation draws closer, she looks forward to only one thing: setting off on her own to study the peaceful inflexions of whale songs. In the meantime, she holds onto her only lifeline: her grandmother, who helps her keep her sanity in the midst of all the noise.

But one day, Solange’s chatter suddenly stops. A mysterious phone call puts her in a state of silent stupor that is so uncharacteristic of her. Eager to understand this sudden change in her mother’s attitude, Capucine uncovers a disturbing family secret: a sister, born several years before her and put up for adoption to avoid scandal. A sister she never knew anything about.

Filled with questions, Capucine travels to the island of Jersey to meet Joy. Do they look alike? Do they have the same red hair, the same eyes? The same love for the open sea?

Along the sandy beaches of Jersey, two sisters get to know each other in a suspended universe where time is punctuated only by the changing tide.