Unnamed mermaid who was swimming near the coast with her baby was chased by a fisherman, she decided to hide her baby in a nearby boat, so she could distract the fisherman and run him ashore. After returning to her baby, she was surprised to find the boat not there, it was docked and a young couple had her baby.
Thirteen years have passed, and each night she still looks at the house where her kid now lives. One time a boy went for a swim in the bay, and she recognized him as her son. Their meeting was interrupted by a fisherman. Few days passed and Cody went for a night swim, this time they met in person, and the mermaid started using her magic on him to complete his merman transformation, but yet again a fisherman intervened with his boat.
The next day Cody showed his girlfriend, Sam, to the mermaid, and Sam found her pretty. Cody fell down in pain and the mermaid wanted to help him, but couldn't get on the shore. The fisherman returned and took Cody on his boat and drove him to a dock. The mermaid followed them, but was captured by the fisherman. The fisherman's own son jumped in and cut the mermaid loose, but was about to drown himself. Cody dove in and rescued him. Mermaid showed herself to all the friends and family of Cody's, and talked with Cody's human adoptive mother via telepathy. She promised to help Cody, and to return him before the school starts. Cody then jumped into the water, and the mermaid helped him to get his tail. They then swam away into the sea.