Criminal Girls: Invite Only

Story-related and cannot be missed.

Used the experimental knight drug on Kisaragi on 4F of Purgatory in the special knighting zone. Every girl is knighted in the same way at the same spot, and all of them will have to be knighted before you can finish Garden of Memories. If you didn't knight them before finishing Purgatory, you'll find what you need somewhere in XF: Warden's Block. Miu and Himekami's experimental drugs will be waiting in the knighting zone once they've faced their sins in the Garden of Memories. Not to worry, none of the knightings are missable.