India Finch is part-human and part-mermaid. In ocean water, special healing powers awaken in her, allowing her to help the merpeople.

However, India longs for greater adventures than healing rashes, so when she hears rumours about Neptune's trident, she decides to search for the powerful tool alongside her mermaid friends.

The four friends soon find themselves facing off against dangerous and deadly mer who want Neptune's power for themselves.

A low reading level, glossary and discussion questions support struggling and reluctant readers.