|This article is about a/an episode in Ultraman Mebius.|
Mirai goes on a date with Aya after catching up with her again. However their date is interrupted by disgruntled Gossip Journalist, Mitsuhiko Hirukawa, and an enemy from Mebius's past.
The scene opens up with four aliens standing together. These aliens are Yapool (in his true giant form,) Deathrem, Glozam, and Alien Mefilas, and together, they form a coalition known as "The Four Heavenly Kings." As Glozam expressing his doubt in Yapool's capabilities to serve alongside them, Yapool gloats that he will kill Mebius and present the Earth to a being known as "the Emperor." With that, Yapool takes off to do his deed, despite Deathrem forbidding him to do so as it is "not his turn."
Back on Earth, Mirai is surprised to see Aya Jinguji again, who in turn reveals that she is the Granddaughter of GUYS's Supreme Chairman Takenaka. Eager to catch up with Mirai again, Aya wishes to go on a date with Mirai and is given permission to do so by a slightly embarrassed but concerned Takenaka and Captain Sakomizu. While walking with Mirai in a city, Aya reveals that she had actually come to see Mirai to confirm something else (she originally stated that she came to see her Grandfather for an Academic Meeting,) but before Mirai can find out what exactly, she dismisses it and she insist on continuing their date. Unknown to Mirai and Aya however, they are being stalked by the Mysterious Man in Black from the previous episode. Also while walking together, Mirai and Aya are also unknowningly watched by Mitsuhiko Hirukawa, the Gossip Journalist who had been writing false stories about George's Sports status and who also had a confrontation with GUYS previously. When confronting Mirai, Hirukawa rudely and invasively questions why he's not helping GUYS, but fortunately, Hirukawa's gossiping is constantly shurgged off by Aya.
Back at GUYS, the other members finally discover the source of the Space-Time Wave that had been attracting the past Aliens to Earth. Tracing its origins to the ocean by Okinoshima, Just as GUYS plan to have it be destroyed by use of a METEOR, they quickly learn that the Source of the Wave is moving. With no other alternative, and with Mirai unable to be contacted, GUYS is forced to go without him as this may be their only chance to stop the Wave and the coming aliens. Using GUYS's own Phoenix Nest again, GUYS takes off after the source. Upon arriving at the Ocean though, the Source of the Wave (revealed to be a Pillar-like Object) bursts out of the Ocean and shoots into the sky, attempting to leave the Atmosphere. GUYS however is already in pursuit and they follow after the Wave into Space.
Back at their date, Mirai and Aya are enjoying some Ice Cream when Mirai hears on a Local News Station of GUYS's departure, and he too in unable to contact them. Concerned about the safety of GUYS, Mirai goes off to return to the base, only to be confronted by the Man in Black. The Man is none other that Yapool himself in a human form, having somehow come to Earth despite his Dimension being sealed shut. Yapool then releases a Red and Gold balloon that takes off into the Sky and it opens up his own Dimension to release another Super Beast: Ace Killer. Ace Killer proceeds to destroy the City while Mirai takes off to battle the Robot. Ordering Aya to save herself, Mirai goes off and transforms into Ultraman Mebius to confront Ace Killer, unaware that Aya had followed and had seen his transformation (to which was what Aya had wanted to confirm by dating Mirai.)
While Mebius fights the Ace Killer, Yapool releases another balloon that reveals the gaseous monster as well, named Gadiba. Having absorbed Mebius's abilities after fighting Red King and Gomora, Gadiba merges with Ace Killer, transforming him into the now dubbed "Mebius Killer," and the newly upgraded Super Beast proceeds to overwhelm Mebius with his very own copied attacks. Aya however motivates Mebius to continue fighting after she reminds him of the last time their met during the assault from the Alien Alliance, and how as an Ultra it's his duty to protect the people. Motivated by her words, Mebius manages to recover and power through Mebius Killer's attacks, and after finding an opening, manages to destroy the Super Beast with a newly acquired technique that Mebius Killer did not copy: The Mebium Dynamite. However, as Yapool points out that despite Mebius Killer and Gadiba's destruction, Mebius's body is now damaged from the Dynamite's recoil and so Mebius collapses and reverts back into Mirai.
Meanwhile back in space, GUYS pursues the Wave's Pillar, which has now landed on the Moon. Before they can dispose of it however, the engines to the Phoenix Nest are cut off by an unknown field, which causes their ship to crash. On Earth, Aya finds Mirai collapsed on the battleground and she consoles him for destroying Mebius Killer, only for Mirai to be taunted by Hirukawa for fainting. Suddenly, Mirai, Aya, and Hirukawa are caught in Yapool's Dimension, which opens up underneath them and swallows them up...
- Aide Toriyama and Maru do not appear in this episode.
- This episode reveals who was behind the Space-Time Wave that had been plaguing Earth between episodes 28-42.
- This is the 2nd (and final) time in the Ultraman Mebius series in which the Phoenix's Nest was launched into battle.
- This episode marks the first time Ultraman Mebius uses his Mebium Dynamite technique
- When Glozam is questioning Yapool's credentials as being a member of the Four Heavenly Kings, Alien Mefilas's "mouth" is seen lighting up, even though he himself is not speaking. (His mouth lights up whenever he speaks.)