Part 1 of 4. After crushing Grimdo, Taiga and the Tri-Squad endeavored to train across the galaxy, only for "the one who controls Zetton", the Space Fear-Demon Zett, to appear before them and attack! In the face of attacking Zettons summoned by the Fear-Demon Zett, the Tri-Squad finds themselves in a desperate situation with no way out! Ultraman Zero and the others come forward with new countermeasures to oppose Absolute Tartarus, the golden giant pulling the strings behind the scenes. The newest member of the Inter Galactic Defense Force, Ultraman Z, joins his reliable senior Ultraman Mebius to face down this absolute conspiracy...!