In their ninth adventure, Rick, Ava, and Emilio explore a river on a tropical island. Suddenly, big tree trunks with strange markings float towards them. A sinister guy threatens them, and mysterious tracks lead them into the deepest jungle. What is going on here? The three friends find themselves in the middle of an exciting adventure which puts not only themselves into danger!
Volume nine in the popular series about the little explorer Rick Nautilus and his two friends, Emilio, descendant of pirates, and Ava, a mermaid.
