A Certain Magical Index NT, Vol. 3 (light novel) — Kazuma Kamachi

Gremlin, a belligerent organization merging magic and science that formed after WWIII, is operating behind the scenes in Hawaii. Under the guidance of Leivinia, leader of Dawn-Colored Sunlight, Touma Kamijou, Mikoto Misaka, Accelerator, Shiage Hamazura, Misaka Worst, and Umidori Kuroyoru head to America's 50th state. But no sooner do they land at New Honolulu International Airport than Gremlin springs a surprise attack on them. Fortunately for Kamijou and company, one man has already clued into Gremlin's schemes and is trying to take them down himself -- Roberto Katze, the President of the United States!