On their way home from a school excursion, Blaize, Umba and Metric, three teenage classmates from the planet Krill who have never previously spoken to each other and are polar opposites in personality, shape and form, are suddenly knocked off course by an electric pulse that's travelling through the universe. They become shipwrecked on the long-forgotten, ancient prison planet of Taos, a threatening world of monsters, magic and secrets, hidden in the universe's Red Zone.

Here, they're greeted by Ginne – a magical, reflective prism. By shaking hands with Umba, Ginne learns that the teens are not a threat but merely lost and good natured so she decides to become their guide. To aid them in their defense against the planet's dark forces, Ginne empowers them with the ability to work together by assembling themselves and combining into one unit – HOLT, a super being who has the wisdom and power of all their planet, parents and ancestors. Holt can fight off most monsters, but he can only sustain his form for a few minutes at a time.

After Blaize, Umba and Metric overhear a strange being's secret message, it becomes clear that the universe is now under attack from an evil, ancient race known as the Ckrook. The teens must now not only survive planet Taos, but also gain allies to fight the Ckrook and help save the universe if they are ever to safely return to Krill, their home.