Alexia, 32, is from Fécamp, a small fishing port on the cliffs of Normandy. In this city in decline, this young maid, flirtatious and lonely trying to escape his daily life. Legs gathered in a large tail covered with scales, she plunges into the sea and escapes. A secret ritual, until the day she decides to register for the Miss Sirène France contest. For a year, she trains tirelessly, doing pool training, jogging in the early morning on the cliffs. As the competition approaches, Alexia opens to the world, exposes herself to the eyes, makes dream, amuses sometimes or disturbs some.

Freshly divorced, Fanny, a thirty-something from Fécamp, has nothing left of her marriage but a sky-blue sofa, debts she refuses to pay, and an absolute determination never to 'start her life' with a man again. Despite her burning need for freedom, this cleaning lady finds herself stuck back at her parents' house. That is, until the day she crosses paths with Anemone, a professional mermaid passing through the region. She decides to take the plunge and dive into the world of mermaiding.

Freshly divorced, Fanny, a thirty-something from Fécamp, has nothing left of her marriage but a sky-blue sofa, debts she refuses to pay, and an absolute determination never to 'start her life' with a man again. Despite her burning need for freedom, this cleaning lady finds herself stuck back at her parents' house. That is, until the day she crosses paths with Anemone, a professional mermaid passing through the region. She decides to take the plunge and dive into the world of mermaiding.