A black cat ghost wandering in Ginza. Koyomi, who was transported six years back in time by the magic of Ghost Script, encounters a living cat and a silver-haired girl named Yumiko. A wizard aiming for her staff, which holds the legacy of a witch. Amidst the melody of Jingle Bells filling the streets, the three of them—two people and one cat—face the time of their decisive battle on the rooftop of a desolate department store. The legendary night when the worm-type virus, Christmas Shopper, was activated is now revealed!