Judging from the amount of time he spends figuring out what to wear, Yuu is not only looking forward to his concert date with Nao, but also seems to be developing some feelings for her. When they meet, he encounters a much more pleasant and bubbly and less surly Nao who is genuinely excited to see ZHIEND live (and collect their very practical smartphone case!)
As the concert progresses, Yuu’s mind-splinter like nagging feeling of deja vu keeps building until it finally explodes when Sala starts singing a song caled “Trigger”, which just happens to be the trigger that sends Yuu…somewhere, somewhen else. Here, he and and a very alive Ayumi are patients/inmates at the very kind of government facility Nao always warned about, where ability users are rounded up and monitored, while those more powerful (and thus dangerous) are restrained, dissected, and/or disposed of.
Is this a flashback, or an alternate reality? The show doesn’t say for sure, nor does it need to. Suffice it to say this is an awesome new direction for a show featuring characters with all sorts of crazy powers, so the ability to travel through time (Yuu’s “big brother” Shunsuke’s ability) isn’t that far out there.
The episode fully commits to this new, harsh, dystopian setting with abandon, along with the efforts by other users to free Shun with Yuu’s true power, “plunder”, or the ability to steal other abilities. That power makes him uniquely suited when the time comes to race through the corridors of the facility to release Shun. In the process, many of his associates fall to the security forces. The time between 13:55 and 17:30 is a thrilling masterpiece in and of itself.
Everything seems to be worth it though, as Shun is released, his eyes uncovered, and…well, something happens. Yuu wakes up in the hospital with Nao by his side, as if it was all a dream, but the timing of Shun using his powers suggests it’s because of Shun that Yuu is here, and was here in this world living peacefully with Ayumi.
Nao is confused by Yuu’s thinking out loud, until a dry Kumagami (who was in the facility with Yuu and Ayumi) enters the room, offering to take Yuu and Nao somewhere where they’ll learn everything they’ve missed out on so far, including reuniting with Shunsuke, who Yuu learns was the one who set Nao on her path of finding and protecting users, thus helping the overall cause. Kumagami also says he can help Yuu rescue Ayumi, as if she wasn’t dead (and indeed, we never saw a body.)
From post-rock concert to dystopian government facility to comfy hospital room, Yuu then finds himself following Kumagami with Nao to another top-secret underground facility, though in this case, it’s the well-funded but time-deficient headquarters and last stronghold of the “resistance” of ability users against the government, an organization led by Shunsuke, who is now blind.
This is little more than a reveal, with Shuu exchanging pleasantries and preparing to tell Yuu and Nao Everything, but this episode had done more than enough already, completely changing the complexion and expanding the scope, stakes, and very reality of the show. This is no longer just about a school club that rescues kids one at a time. This is about saving them all, including Ayumi. I’m always suspicious of un-killing characters, but in this case I’m very intrigued to see how they do it.