Ariel, a young and beautiful sixteen-year-old mermaid, princess of the kingdom of Atlantica, is not satisfied with her underwater life and is fascinated by the human world.

With her best fish friend, she collects objects from this world and often goes to the surface to visit a seagull.

She ignores the warnings of her father, King Triton, ruler of Atlantica, and Sebastian, a crab who is also the king's advisor and conductor, who tell her that contact between humans and the people of the sea is forbidden.