Zixx is thrilled when her team enters Level Three intact. The challenges of Level Three turn out to be far greater than the previous levels, requiring puzzle solving to gain upgrades and somewhere on this level in the Keep, Onccalon is growing ever stronger and is about to be resurrected. Only the most powerful weapon of all time can defeat Onccalon, and so the race is on to find the Sword of Gaanth, which is split into a hilt, a blade and six Vortrian gems. If they fail, then the last remaining Gaanth who resides within the sword will destroy the entire universe before Onccalon can rule it. In the end, Onccalon is destroyed by Zixx using the Gaanth, and Zixx, Flanngo and Tarphex go back to their home planet.