Together with his colleague Miyazawa Kenji, Nakajima Atsushi assumes his normal duties at the Armed Detective Agency, where Izumi Kyoka has also been accepted.

But just as life is returning to normal following the clash with the Port Mafia, a troublesome group of American Ability users called the Guild appears.

Their boss F. Scott Fitzgerald approaches Agency director Fukuzawa Yukichi with a proposal...!?

Meanwhile, Atsushi becomes the target of the Guild's bizarre assassin - L.M. Montgomery!