Just as BoBoiBoy makes progress on wielding his Third Tier Elemental Powers, a shadowy newcomer captures his best friend and challenges him to a duel.

BoBoiBoy must make a difficult choice as he and his friends travel to the planet Windara and witness the cruel reign of the traitor Reramos.

BoBoiBoy and Fang crash-land in a desert, far from their crew. Soon, they fall into a trap set by Windara's inhabitants. But are they friends or foes?

Determined to stop Reramos from controlling Windara, BoBoiBoy and the crew sneak into Kupuri Castle to free Princess Kuputeri.

As Reramos transforms into a gigantic monstrous creature, BoBoiBoy must find a way to unleash the Tempest Power to stand a chance against him.