Once upon a time, someone named Pill thought about having fun at a great library. After a little training with Kung Fu Man at the Mountainside Temple, Pill sets off for the Scarlet Devil Mansion in Gensokyo. However, every now and then she runs into a few Wild Pokémon, with one of them being a Chespin. After she makes her way to the mansion, she finds Rohan Kishibe somewhere in the library, claiming he wants to make story material out of her. After the two fight, Patchouli Knowledge comes in saying "WHAT THE HECK ARE YOU DOING IN MY LIBRARY" and fights Pill.
Once she's done with the librarian, Sakuya Izayoi enters the library and says "wait what are you doing in the mansion without master Remilia's permission?" and fights Pill, only to lose. AND THEN that Chris kid randomly comes in to the Library and fights Pill! Eventually, she got evicted from the Mansion for her violent behavior and left for the Forest of Dolls to find a kid named Shingo Yabuki.
After a thourough ass kicking, Pill decided that she wanted revenge on the people at the Scarlet Devil Mansion for kicking her out, and stormed back into it's Library. Naturally, Patchouli wasn't impressed at the slightest and sent out Clone Koa to deal with the intruder once and for all. However, the succubi failed to stop Pill, so Patchy had to take a desparate measure: Let the Buhddists deal with the problem. So she ejected Pill out of the mansion with powerful magic and sent them flying towards Byakuren's flying Palanquin Ship. After the group was misunderstood by Pill's "attack" on the ship, Byakuren herself shows up saying that she sadly can't settle this peacefully. They were evenly matched, until Pill ultimately manages to defeat Byakuren, proclaiming she is the strongest fighter, only for the credits to roll mid-speech.
And then everyone died. The end.