Optimus Prime follows his friend Megatron to Elementros, a planet holding mysterious powers. There he meets Lightlong, a giraffe-type Transformer and one of the energy beasts that live on the planet in the shape of animals and dinosaurs. Lightlong explains that these beasts carry five kinds of element energy within them: fire, water, earth, nature, and lightning. When Megatron suddenly attacks, the bond between Optimus and Lightlong awakens the ability to transform and combine into Wild King. Optimus sides with the animals while Megatron leads the dinosaurs, setting up a mecha action clash across this sci-fi world.