((After hearing about the party at the Scarlet Devil Mansion where everyone in Gensokyo was invited, you decided that was a good chance to visit it and meet the residents for yourself.))

As you're walking through the giant library, a red haired girl with a pair of bat wings on her head as well as one her back floats down in front of you. — Aha! A human came to the library! Patchouli-san won't like this! Buuut... The name's Koakuma, how can I help ya?