A Certain Magical Index, Vol. 19 (light novel) — Kazuma Kamachi

In the shadows of Academy City, the special team known only as Group is hard at work to solve yet another incident. The Level 5 esper Accelerator and the man who controls both supernatural and magic powers, Tsuchimikado, are investigating a case where their only clue is the word "dragon." While they struggle to find a way to make progress, a member of Academy City's board of directors bears a terrible grudge against them. Once again, Group finds themselves on the business end of a fearsome weapon!