Taro chronicles the exploits of Ultra Brothers, Ultraman Mebius and Ultraman Zero to his son Taiga, as well as receiving visions of Ultraman Titas and Fuma. This special is streamed on Tsuburaya Production's YouTube channel for two weeks before the premier of the series and uses clips from Ultraman Saga, Ultraman Mebius Side Story: Ghost Reverse and Ultra Zero Fight.^[1]

The Tri-Squad and New Generation Heroes fought against Tregear in a fight which caused the former team to disappear in space. 12 years later, E.G.I.S. officers Hiroyuki and Homare try to escort the Alien Rivers Kawazu in order to deliver a Baby Zandrias, but their deal was cut short after he paid for their service, leading to the child being captured by the Alien Magma to lure its mother into fighting Zegun for the Villain Guild to sell their monster for auction. When Kirisaki summoned Hellberus, it killed Zegun and try to attack the Zandrias family before Hiroyuki's resolve to save the baby allow him to become one with the Ultraman named Taiga. After saving the child, he defeated Hellberus with Ultraman Orb's Orb-let with both Ultra and the youth witnessing the Zandrias family's departure.^[2]

12 years prior, Hiroyuki bonded with Taiga's scattered particles of light after a failed attempt to save the baby Guesra, Chibisuke. In the present day, E.G.I.S. was requested by External Affairs Division X to hunt a trio of aliens and their monster King Guesra during their target on cacao bean supplies. Recognizing that King Guesra is in fact Chibisuke, Hiroyuki attempts to bring his friend to its senses until Tregear appears and kills the monster in cold-blood.^[2]

After being killed in a satellite explosion, Rento was revived by Tregear to exact his revenge on the Cozmo Technica president Imazato. He appeared a month after the incident and faced against E.G.I.S. members Hiroyuki and Homare, who was assigned to protect the president. When Rento becomes Galactron MK2 and fought Taiga, Titas purify his spirit by reuniting him with Nana, allowing them to pass on to the afterlife. With Galactron and a descending satellite destroyed, Titas had a brief fight with Tregear before adjusting his life as Hiroyuki's second Ultraman.^[2]

External Affairs Division X requested help from E.G.I.S. when a trio of rogue members from Villain Guild set up a monster bomb.^[2] After getting the information from Fanton and Zolin, Homare and Hiroyuki were kidnapped by Volk and his cohorts until an assassin sent by Zolin attacked them. As Taiga fought against Darebolic (MB) in the city, a dying Volk revealed that he was deceived by Kirisaki and his wish is to help the impoverished alien children. From his jewelry, Fuma appeared and reunited with the Tri-Squad, using his speed to disorient and destroy Darebolic (MB). Tregear interfered once more and retreated after shrugging off Fuma's attack.

Following the first defeat of Segmeger, Alien Damara appeared and reveal that the monster will remain exist so long that its summoner is still around. With the injured Hiroyuki analyzed every available cameras, Pirika took on the surveillance mission and met Aoi as they skipped their respective jobs to hang out. After her true nature as an Alien Seger exposed, she summoned Segmeger to wreak havoc on the city. While the monster managed to defeat all three members of Tri-Squad, Pirika managed to encourage Aoi to choose her own path as Aoi sacrificed herself to heal Titas and brought an end to the monster.

The Alien Gapiya "Abel" was hired by Tregear to kill the Tri-Squad but spends the remainder of the episode trying to hunt Kana and a homesick alien who wanted Abel's help to leave Earth. As the Tri-Squad fought against Abel, Kana managed to make the alien rethink of his decision to leave Earth as he finally agreed that he liked the planet and wished to spend more time in it.

As the tension between humans and aliens begin to grow, Pirika's attempt to sacrifice herself in order to eliminate Woola leads to the realization that it was only cursed by its own hunger. Former Villain Guild members Alien Magma and Merkind offer their assistance to neutralize Woola as Taiga fed the monster with his and Tregear's energy, ending the monster's life in a peaceful way. After rejecting his last chance at redemption, Tregear fought against Taiga Tri-Strium and seemingly obliterated by exposing himself to the Quattro Squad Blaster, seeing Taro's image in the young hero in his final moments.