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.

The Tennysons arrive at a swamp, where a festivities of Gatorfest start first thing the next day. Gwen finds Ben playing around with the Omnitrix, and she warns him that it may create unusual problems. Without heeding Max and Gwen's warning, he pops the face out, and the Omnitrix acts up. Right away, something was wrong, though it was gone unnoticed, at least, until the next day. Gator-fest was going along well, but the giant frog of Dr. Animo comes in to disrupt it. Dr. Animo has returned, and he wants to take revenge on Ben. But when Ben goes alien, he transforms into a hybrid alien with unbalanced attributes. Will Ben ever learn his lesson in listening for a change?