Lily's a young girL with a best friend, Manlo, who regales her about the ocean far away from the lagoon where they meet each day and talk. he offers her an adventure to go and see all he has been telling her about. She will become a mermaid in order to go with Mango. Lily is so excited she agrees to his offer without asking questions what it all it entails.
As best friends Mano believes what he wants in life is the same Lily wants. Manlo takes her to places she heard of and those she hasn't but their adventure takes a turn and Lily's found she agreed to more than she realised because she didn't ask questions about the transition.