The story begins moments before the destruction of Planet Tek. Princess Tekla and Voxx, her robotic companion, flee their world as it is consumed by the Beast Planet and escape attacking Beast Drones. She escapes her solar system to the system of the Cluster through a Beast Armada hole in space. Tekla travels to the Cluster to warn them of the approaching danger. As she travels through the system, the Beast attacks her and she crashes on Planet Ice, where she is rescued by Graveheart. Soon the Beast attacks, which convinces King Cryos to form an alliance of the Cluster worlds against the Beast Planet. The first season revolves around Graveheart's, who has become the de facto leader of the Alliance, efforts to convince the leaders of the other Cluster worlds to join the Alliance. The first planet they visit is Planet Rock, but under Lord Mantle's leadership, they feel that the Battlemoons are enough to defend their planet, and do not join the Alliance but Graveheart's friend Jade joins him to help rally planets Fire and Bone to his cause, after an attack on Planet Rock by Beast Drones. In the end, Planets Fire and Bone join the Alliance and they soon realize that the Beast Planet must have set up a base somewhere nearby from which it is launching its attacks on the Alliance. They find out that it is Remora and the three worlds send a huge fleet to wipe out the Beast Drones on the planet, but the destruction of Remora only serves to anger the newly arrived Beast Planet. Planet Rock has now joined the Alliance, using its five powerful Battle Moons to help destroy Remora, but the Beast Planet destroys one of the moons with ease from half way across the solar system, and sets out to consume Planet Fire.
Another moon is lost in the battle to defend Planet Fire and nothing is able to stop the Beast Planet. Planet Ice is almost destroyed in the battle but Tekla discovers the World Engines and saves the planet and as the Alliance relocates the people of Planet Fire to the Battle Moons, the World Engines on Fire are also activated. But Fire’s engines are damaged by the Beast Drones and the planet is too slow to avoid the Beast Planet. The Grand Vizier then uses the engines to ram the Beast Planet with Planet Fire. Fire is consumed by the Beast Planet and the rest of the Alliance worlds use their engines to move away from the Beast Planet. On their journey, they discover Planet Sand which joins the Alliance and Planet Jungle, which the Alliance uses as a trap. They fill it with enough explosives to destroy the planet and detonate them as the Beast Planet consumes it, but the Beast Planet is still in one piece. The inhabitants of Jungle survive when a single plant is given to the Alliance. The Prison Planet then teleports into the path of the Alliance and Graveheart, Jade, Cryos and Emperor Femur are sent to investigate but they all crash on the planet. As a rescue is about to be attempted, the Prison Planet teleports away.
On the Prison Planet, Graveheart and Cryos are captured by a faction of convicts led by Jewelia, a devious woman who takes a liking to Graveheart. Femur, unfortunately for him, is taken, along with Jade, by a second faction commanded by Sternum, Femur’s nobler brother, and arguably the rightful ruler of Planet Bone. Convinced that their friends have been slain by the other faction, the two pairs join the fight on the side of their respective faction until the truth is revealed.
Meanwhile, the Beast Drones attack the Alliance and Lord Mantle takes control of the Alliance by force. Thinking that his planet is superior to the Beast Planet, Mantle sends the Battle Moons to attack the Beast Planet, but an armada of Beast ships capture Planet Rock and Blokk kills Lord Mantle in single combat. As the Beast Planet is about to consume Planet Rock, the Prison Planet teleports into its path and as it is being consumed Graveheart and his group use Sternum's Telepod to travel to Rock and they then teleport the Prison Planet away and it takes the Beast Planet with it. A final battle between Graveheart and Blokk results in Blokk’s demise, Jade’s rise to ruler of Planet Rock and the Alliances new era of peace. Meanwhile, the story ends moments before the destruction of Planet Reptizar at the hands of the Beast Planet.