Ryuu and Shinpei are able to catch Ushio before she falls to her death, and she’s reverted to a child since her hair wasn’t quite enough to fully restore her. She’s well and truly out of gas and can no longer fight, but has one more ace up her sleeve.
If Ryuu and Shinpei can buy her two minutes, she’ll turn herself into a hacking shotgun shell that, once fired at Shide, will sever his connection to Hiruko and delete him. While stalling that long won’t be easy, it’s far from impossible, especially as Shide is the loquacious type and enjoys toying with his prey.
Ryuu and Shinpei do battle with Shide, who in addition to being very annoying with his monologues is also a tough customer due to three centuries of honing his shadow skills. Neither of the boys can match him for pure creativity, and Shin can tell they’re not going to make it if they don’t do something drastic.
That something is having Ryuu possess Shide’s armor, depicted as Ryuu literally wrestling with a mass of mud with eyeballs, resulting in Shide being frozen in place. The downside is that now that Ryuu is out of Shin’s body, Shin can feel all the pain Ryuu was suppressing. He nearly passes out, and then his body starts to disintegrate.
However, all this rash, all-or-nothing action pays off, as Ushio is able to finish the hacking shell. This leaves Shin having to get to the shotgun two meters away before Shide (who isolates Ryuu and tosses him away in a glob of mud) can charge and kill him.
He won’t make it, and Ushio can’t move the shotgun as she’s the shell inside, but Haine can, and moves the gun right into Shinpei’s hands. Ushio helps him hold it steady, they get the shot off, and Shide finally, finally bites the dust. His plans to both cause and witness the end of the world come to nothing.
This leaves Shinpei, Ushio, Ryuu, Haine, and lil’ baby Hiruko, whom Ushio attempts to delete. Instead her and everyone else’s data is transported to the real world of over 300 years ago, the very day that the original Haine finds the dead whale that is Hiruko on the beach.
Realizing that Hiruko sent them back to break the cycle, Shinpei scares Haine off before she reaches the whale, and then Ushio deletes it. Baby Hiruko vanishes, finally able to rest. Haine vanishes shortly thereafter, hoping that she and Ryuu can be friends again somewhere, someplace.
That just leaves Shinpei and Ushio on the beach, and what we know must be one more tearful goodbye. Ushio is a shadow, after all, and with Hiruko gone she’s not far behind.
Shinpei wants to disappear with her, but she throws a characteristic “dummy” his way; the time they got to spend together in the past few days made her—made them both—so happy, but she wants him to live on. Not to mention everyone is waiting for Shinpei back home in 2018. Ushio vows to use her remaining power to transport him back to his proper time, but that’s not all she aims to do.
It would seem she’s inherited at least some of Hiruko’s power, with which she plans to overcome the loops and re-draw the summer. So as Shinpei ends up on the boat to the island, his face landing in Hizuru’s chest, maybe it’s not goodbye, but more of a see you later situation. We’ll find out in the finale.