As the Nektons explore a mysterious tunnel behind a huge undersea waterfall, strange creatures and strong currents surprise them at every turn. Everything is not as it seems. The true nature of the tunnel will astonish them.

Fontaine and Smiling Finn get stuck inside a giant clam as the dark orca pirates battle the Nektons for the giant pearl within! Air is scarce and time is running out. Can the pirates and Nektons work together to save them?