A Warhammer 40k Xover. In the nightmare future of the 41st millennium, there is only war. For three small fillies who knew only peace, this is a terrifying change. But there is hope for them. They can survive. But the Marks of War will change them.
Drafted into the defense of Equestria, the Crusaders volunteer to embark a series of dangerous operations behind enemy lines to cripple one of their chief technological advantages, a revolutionary spell matrix that Twilight refers to as the "radio."