In the glittering lights of Christmas, the stage is set in New York. Akari Kido, a Tokyo Metropolitan Police officer on duty for an international exchange program, is busy regulating traffic flow. Just then, a witch-like apparition plays a mischievous trick for a "Christmas Party" celebration. But as a trailer truck hurtles towards her at full speed, an enigmatic girl materializes out of nowhere and cries, "I'll protect both New York and Akari!"