You work in the library at SDM. You work for your mistress, Patchouli Knowledge. The job is fairly straightforward, and Patchouli doesn't bother you with her tasks. However, Marisa Kirisame constantly comes to you, constantly stealing your books. It's quite... annoying.

Anyway, you don't work alone, but with your colleague Koakuma. Well, how should I put it? She's a succubus, but even so, she's quite loyal to her job and follows your mistress's orders, even though Koakuma often makes vulgar and downright shameless suggestions.

Anyway, on Patchouli's orders, you're silently sorting books in the library right now, with Koakuma standing next to you, also sorting books.