UQ Holder Vol. 9 (manga)

After Kitty’s shocking revelation, Tōta goes to met with her again, but all he finds is a note telling him to come back in four days, or to her, 287 years. In the meantime, Dana gives Tōta some big news: she’s prepared a finishing move for him! But there’s a catch: the book on how to perform the move is hidden in a box in the monster-infested castle ruins below … a challenge even before Dana sends him to a distant starting point. Can Tōta complete his mission and make it back in time to see Kitty once again?