Two years after Kengo merged into the Eternity Core as Ultraman Trigger to stabilize it, GUTS-Select and their new leader Ryuichi Tokioka deal with a new wave of monster attacks before being assigned to investigate the Leyrah cult, a terrorist group seeking to restore the Ultra Ancient Civilization. The group learn from the cult's captured leader, Leyrah Ibra, relays his message of the Eternity Core and Kengo's impending doom to Yuna, and that to save them both require the help of Yuzare and the Ancient Sparklence. GUTS-Select agrees with the temporary alliance to enact a ritual to extract Kengo from the Eternity Core, with Kengo's Hyper Keys scattered in the process. Following a brief celebration, Ibra escapes while using a Pagos to attack TPU headquarters as a diversion. The monster is quickly defeated by Ultraman Z, revealing he and Haruki were on the tracking down the alien parasite Celebro after it escaped from STORAGE’s captivity. As Haruki and Z's search led them to Kengo’s Earth, the group deduce that Celebro is hiding amongst the Leyrah cultists and decide to track the cult down while locating Trigger's Hyper Keys.
