Whilst exploring a Sage's Puzzle in England with Jin in the hopes of recovering his memory, Kaito stumbles upon an unsolved puzzle, having assumed Jin had already solved all of them. Solving the puzzle with ease, Kaito discovers a brooch with a cat engraved on it, which Jin takes an interest in. Later, they, along with Nonoha and Rook, go to the Fool's Puzzle where Kaito and Rook previously faced off against each other, where they encounter a strange girl named Raetsel, who takes the brooch and runs off with Jin inside the puzzle, activating its traps...