Our heroes ride a jet belonging to Grandpa Max's old Friend, Donovan Grand Smith, who owns an underwater resort. At the entrance, they receive a warm welcome from Donovan himself, though they also meet with his grandson, Edwin, who didn't seem to be excited about their guests. Later, when Edwin, Ben, and Gwen enter the Undersea Manta Ray, a giant submarine, they encounter strange aliens that threatened to destroy the whole resort. While the kids find a way to cooperate with each other to find the source that lures them in, Donovan himself learns a few lessons in how to bond better with his grandson.
Elenco: Ashley Johnson , Charlie Schlatter , Dwight Schultz , Greg Cipes , Greg Ellis , Jeff Bennett , Jim Ward , John DiMaggio , Kevin Conroy , Kevin Michael Richardson , Michael Dorn , Peter Renaday , Richard Green , Rob Paulsen , Robin Atkin Downes , Tom Kane , Vicki Lewis , Yuri Lowenthal , Jennifer Hale , Kari Wahlgren , Khary Payton , Tara Strong , Claudia Schmidt , Meagan Smith , Paul Eiding , Ulf Söhmisch , Dee Bradley Baker , Fred Tatasciore , Richard McGonagle , Richard Steven Horvitz .