A Certain Magical Index, Vol. 21 (light novel)

As war continues to threaten to change the entire planet as they know it, three young boys are each desperately searching for the answers to their troubles in Russia. Hamazura is still looking for any clues to how he might be able to cure his friend's condition. Accelerator can't stop until he finds a way to save one helpless girl. And Kamijou won't give up on returning Index back to normal, no matter who stands in his way!