A Certain Magical Index, Vol. 12 (light novel) — Kazuma Kamachi

Though he gave his all during the festival to save Academy City, Touma still spectacularly lost his bet with Mikoto. Now he's a slave to her every order until she's completely satisfied! But that's the least of his worries--a jealous Kuroko just might kill him, Little Misaka is about to explode, Index is nowhere to be found, and then there's this girl who seems totally lost... Meanwhile, Accelerator is busy settling into his new life when he notices Last Order is missing. Fearing the worst, the former villain launches a frantic search only to find a starving girl in a white nun's habit...