Mundum divit factum, atqur pulchre
Altair’s devastated to see that Souta has stooped as low as to use Setsuna’s death against her; Souta makes no apologies for his “cowardly act.” He will do whatever it takes to stop Altair.
The Setsuna-creation comes down the station steps and approaches Altair. Altair refuses to accept this illusion of her creator, but also can’t bring herself to harm her either. This 
fake Setsuna is aware that she is not real, and it’s clear she’s been designed based on some of Souta’s memories of her, plus some of Setsuna’s own “lost memories.” She’s also aware that the real version of herself is dead because she threw herself in front of a train.
Setsuna feels that it’s a miracle that she’s been brought back, so she can see and talk to Altair at least this once. Setsuna tries to apologize to Altair for giving her all of her unhappy thoughts and sad wishes, because she knows that mixed in with Altair’s good and bad parts were angry, destructive feelings towards the world that had turned against her. But Altair doesn’t blame Setsuna and says that her decision to destroy the human world on Setsuna’s behalf was her decision alone.
The two creations reconcile with each other and it seems like the destruction of the human world at Altair’s hands might be averted. Then the Setsuna-creation acknowledges that she can’t exist because her real self is dead. She moves to kill herself in front of an oncoming train as the real Setsuna did, but Altair refuses to let her die. Altair also throws herself in front of the train alongside “Setsuna” and uses one of her Holopsicon abilities to create a brand new universe where the two of them can live together. Keep in mind that the audience is watching all of these events as they’re occurring (in dead silence); Meteora confirms that they are accepting what they’re seeing.
Altair and Setsuna awaken in an unknown world, on a plain covered in a few inches of water. It looks like the two of them are alone. For the first time, we see Altair smile like a
normal person. Altair says they can stay in this new universe together, forever, and together they can create an “infinite story” – to become gods, if you will. They will create each other’s stories and become gods by being creators.
Altair hands the Setsuna-illusion her glasses, and the latter acknowledges that they’re not her glasses. After a pause she remembers that they’re Souta’s. “Setsuna” explains to Altair that the glasses are super important because they’re from the person she wanted to introduce Altair to. That’s why she drew Altair, after all.
Souta is openly crying at this point, and he talks to this illusion of Setsuna as if she were real and alive again. He explains that he was scared to walk beside her when she was much more talented than he was, even though he wanted to be with her so badly. And in the end he ended up “standing still” while she was beat up by cyberbullies and eventually took her own life. Souta explains that this time he got the help of his friends and some other creators, and he tried his very best when he created her, so that for once he could try to see the same world that she did. Still crying, Souta goes on to say that he poured his heart into creating this replica of Setsuna as he used to know her, and as the screens monitoring the birdcage turn to static, Souta asks his Setsuna creation if he was finally able to catch up to her in terms of skill.
My thoughts: *still crying over my keyboard*
One episode left!
I wonder how they’ll tie up loose ends and end the story itself.
Any guesses?