A certain unlikely hero...October 18—World War III has begun. As the flames of conflict between Academy City and Russia spread further, the rest of the world suddenly finds itself pulled into the fight. Fiamma, the only remaining active member of God’s Right Seat, attempts to control everything from the shadows while others run straight into the heart of the firestorm to do what the can!Kamijou will travel as far as he must to revive the magically comatose Index. Accelerator won’t let even a war stop him from saving Last Order. And Hamazura must find a way to heal Takitsubo’s stimulant-riddled body. Though their goals are different, fate will force these three to cross path in Russia where something sinister lies in wait for them...!

Seven days have passed since the start of the Daihasei Festival, one of the biggest events of Academy City. Everyone is participating--Seiri Fukiyose is helping coordinate the games, Komoe Tsukuyomi dresses for the part as she cheers for her students, and of course, famous Mikoto Misaka is blowing away the competition. Even Kamijou has appearances! But a shadow has fallen across the celebrations: The Croce di Pietro. This magical artifact threatens the livelihoods of everyone Kamijou holds dear so he dashes off to try and bring Academy City back from the brink. But Oriana Thompson, the magician known as Route Disturb, and the Roman Catholic Church are determined to bring the bastion of science to its knees. Kamijou is going to need all the help he can get-and some luck for once wouldn't hurt!

Touma Kamijou just can't catch a break. He might live in Academy City, a place full of more super powered students than you can shake a stick at, but his only superpower is his supernatural lack of luck. He wants nothing more than to keep a low profile, but when a girl named Index comes into his life, it gets more complicated and dangerous than ever!

Item’s battle comes to a head as their hideout is raided, and the team reaches its breaking point. Disgusted with Mugino’s disregard for the other members’ lives, Hamazura finds the resolve to stand up to her. Mugino may be a Level Five, one of the strongest espers in Academy City, but she’ll see that even a powerless Level Zero like Hamazura can put up a fight when his back is against the wall!

Accelerator’s first mission for the enigmatic organization Group starts. It seems simple—take down the rebellious Level Zero force Skill-Out. Mysterious benefactors, unlikely allies, and the appearance of a new faction make it anything but. The prelude of war is upon Academy City!

"First published in Japan in 2019 by Square Enix Co., Ltd."--Colophon.

Itsuwa and the Amakusa Church struggle to defend Touma from Acqua of the Back, but it seems like even their combined strength won’t be enough...until their own ace in the hole arrives! Kaori Kanzaki returns to aid her comrades in their hour of need, setting the stage for a deadly duel. Will there be anything left of Academy City after the two saints clash?