

While taking in the sights and sounds of a Rio de Jenaro music festival, Ben bristles at Gwen's suggestion that she be his new sidekick, but when the festival is threaten by the strong supersonic waves of Lord Decibel, our hero must lean on help from Gwen and Max in order to defeat him.
When Grandpa Max’s engineer buddy Phil Billings gifts Team Tennyson the Omni-Copter, a state of the art flying vehicle that can transport the Rustbucket for overseas adventures, Steam Smythe takes to the skies to ground Ben and company’s first test flight; but unbeknownst to our heroes, Smythe was sent to battle Ben’s latest alien forms by a mysterious, powerful enemy: the Forever Knight.
During one last stop by a toy store before Ben, Gwen, and Grandpa Max's maiden voyage across the Atlantic, Ben runs into an old bully, Kevin 11, who now has new powers. He's able to transform into aliens just like Ben, such as the "bootleg" doppelganger of Cannon-bolt—Wrecking-bolt!