Alice Liddell returns from yet another journey from the Otherlands. Although still recovering from the pain of her past, a revelation has served as a catalyst to further either her growth or her destruction. Enrolled at Hogwarts School of Witchcraft and Wizardry, Alice is prophesied as a hero that will save the world from the impending doom in the near future, prophesied to save reality through saving someone's Wonderland.

Alice Liddell is the key of the prophecy, and her madness will save everyone's sanity.

an Alice: Madness Returns X Harry Potter crossover fanfiction