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!

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!

In London, the women's dorm in a magicians' base get wild, while in the underbelly of Academy City, Accelerator stumbles upon someone who has been waiting for him all this time.

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!

To quash an attack by God’s Right Seat on Academy City, the mysterious Aleister Crowley will utilize even the corrupted power of an angel. But when Touma discovers that angel’s identity, he’ll stop at nothing to save her. Meanwhile, Accelerator is on a mission of his own to rescue Last Order from the ruthless Kihara. Could these seemingly unrelated battles actually be two sides of the same coin…?!

A certain unlikely hero...Fiamma’s plans have finally been set in motion. His ultimate creation, the massive Star of Bethlehem, dominates the skies over Russia. Now he stands ready to purge everything and everyone unnecessary to his grand mission to save humanity. Down below, sorcerer, soldier, and student alike are fighting for their lives against a new calamity that threatens the entire world. After following Fiamma so far for so long, Kamijou knows that there’s only one way to put an end to this crisis: Defeat Fiamma and destroy his flying fortress—even if it means challenging God’s Right Seat all alone. Rotten luck or not, Kamijou has to do it. After all, Index is still waiting for him...!

The horrifying experiment to make Accelerator into an all-powerful Level Six has commenced--and it involves the wholesale slaughter of the little sisters cloned from Mikoto Misaka. Can Touma find a way to stop the seemingly invincible Accelerator? Could it be that weakness is stronger than strength could ever be?