Sophia liked nothing more than to swim around the ocean and play all day. The trouble with that was the fact that she kept setting her tiara down and swimming off. Her parents told her to take better care of such an important item, but Sophia couldn't help herself! The tiara made her feel pretty as she explored her underwater world. Then, one day, the unthinkable happens. She can't remember where she left the tiara and sets out to find the treasured item. The ocean is no place for a young mermaid alone and Sophia must face danger and realize her parents set rules for very good reasons.