Koakuma Teeri to Kyuuseishu!?

I, Souichiro, picked up this little girl on a certain rainy day. Even though she has pink hair and unfamiliar cosplay looking clothes, she is just a normal girl. If there is one thing not normal, then that would be ---the single black wing, which is growing out from her back. She who claims to be a devil, says that she has no place to return to, so...