1965: outside a small house on the coast of St. Thomas, four dolphins are circling in a pool. This is where Cora, newly arrived on the island, finds them by accident, as though they've been waiting for her. She won't discover the motives of the scientists working in the house until later, but by then her apparent connection with the animals--aided by her own deafness--has given her every reason to stay.

The house is a research facility led by the obsessive Dr. Blum, a man aiming to teach the dolphins' human language. To stave off some of Blum's more insidious experimentations, Cora suggests they build a flooded apartment where she can live and speak with the youngest dolphin around the clock.

The radical research forges ahead, but Blum has other ideas and Cora's instincts clash with the male-dominated world of science in the sixties. As a terrible scandal threatens to engulf the experiment, Cora's determination to save the dolphins becomes a battle to save herself.