In the year 1889, in the mystical city of London, the phantom thief Lupin sets his sights on Mr. Fogg's prized possession, the black diamond known as “The Penultimate Night.” It lies deep within the mansion's underground, sealed behind layers of iron doors and locks, inside an impenetrable pure silver safe. To most, it would seem impossible for Lupin to even break in, let alone steal the black diamond. And yet…!? The detective who specializes in “supernatural cases”-The Birdcage User-is about to face off against Lupin at last!