The Royal Guard has intensified their training regimen after countless attacks on Canterlot. After months of hard training, they only accept the best of the best. Pipsqueak signs up to join these elite soldiers in order to protect a certain princess.
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."