Discover a spectacular animated world where good meets evil in a sci-fi collision of high technology and mythic fantasy. When the Lightstar Crystal is split into two, the kingdom of Luminicity is plunged into darkness and divided into two warring factions. Now, the rightful heirs to the throne must come together to battle the powerful forces of the evil Baron Dark and reunite the two halves of the crystal before their world slips into the shadows forever!

Someone has betrayed the humans and the Legion of Light is captured by Baron Dark. All fingers point to their brother Grimskull because he has the ability to mentally connect with the evil Baron Dark.

For the first time, the humans discover a way to stop a Skeleton Warrior when Talyn discovers that by removing a Warrior’s heartstone, that Warrior is instantly refleshed. Ferris leaves the Legion of Light, unable to trust himself after his transformation, but he finds enough courage to warn the Legion of Light of a surprise attack and say goodbye to Talyn.

Grimskull and some Legion of Light commandos investigate what is believed to be Baron Dark’s new Crystal Chamber, but instead find a data crystal. While wondering why Dark wants the Legion to have the crystal so badly, Grimskull escapes an ambush of Skeleton Warriors, during which the commandos are captured. The data crystal reveals footage from when the Lightstar Crystal was split, which also reveals Joshua’s tragic mistake. The angry refugees brand Grimskull a traitor and are prepared to have him executed when Prince Lightstar steps in but now Grimskull needs to find a way to rescue both the hostages and his older brother.

A young woman named Zara, who also happens to be an old flame of Justin Lightstar, appeals to the Legion of Light for help when Baron Dark and the Skeleton Warriors invade her village stealing food and medical supplies. The Legion agrees to help, but during the mission, Justin and Grimskull are forced to relive old hurts and past memories of the young woman they both still care for.