Join the Mistika as they journey into the Swamp of Secrets and continue to Battle for Power in the giant cave of Karda Nui!
Battles continue to rage in Karda Nui, the core of the universe. While half the Toa Nuva and their Matoran friends defend the skies from bat-like Makuta, the other three heroes – Toa Tahu, Toa Gali, and Toa Onua – plunge to the swamp far below in search of the Mask of Life. Unknown to the three, the Mask of Life has created a body for itself and joined the fight above as Toa Ignika.
But they’re not alone. Three more Makuta, mutated by toxic swamp waters, ambush the three heroes as they search the dense, murky undergrowth. Even though the Toa Nuva are armed with new Nynrah Ghost blasters, these insect-like Makuta – Krika, Bitil, and Gorast – battle the Toa for possession of keystones. These stones are the means to unlock the secrets of awakening the Great Spirit Mata Nui.
Meanwhile, with the aid of Toa Ignika, Lewa, Pohatu, and Kopaka get the upper hand over their Makuta enemies, forcing them to retreat down to the swamp and their insectoid brothers.
Below, Tahu discovers a metal sphere embedded in a fallen stalactite, its smooth surface covered with concentric circle patterns. The object is surrounded by a protective shield, which the Toa Nuva can’t get through.
The remaining Toa Nuva, accompanied by a strangely altered Takanuva, Toa of Light, and the mysterious Toa Ignika, team up with their friends in the swamp. Confronted by eight powerful Makuta, the heroes band together and finally find a way to defeat their enemies in time to awaken the Great Spirit Mata Nui. Tahu finally pierces the Codrex shell, and inside they find ancient machinery, vehicles… and the secret to the Toa.
While some Toa hop onto the powerful flying vehicles to evacuate all the Matoran, the rest convince Toa Ignika that the only way to awaken Mata Nui and save the universe is for him to give up his new-found life and jump-start Mata Nui’s consciousness. Reluctantly, but remembering Matoro’s sacrifice, Toa Ignika agrees. The remainder of the Toa and the last of the av-Matoran race toward an exit portal, hoping to outrun the deadly energy storm that will be triggered when the Mask of Life is placed in the Codrex. They make it out in time, but the Makuta are not so lucky… they perish in the storm that fills Karda Nui.
Slowly, machinery starts grinding in the depths of the cavern, as something begins to happen to the entire universe…