This is a cool doujin that doesn't actually make sense without the context of the original (go read it, it's three chapters and good enough). It's really just letting us exploring one of the characters more, since y'know, three chapters
If you want to understand the context, buy Mahoutsukai no Yoru on the Nintendo Switch and PS4, available now!
Either that or you can wait for the anime adaptation by ufotable
