Members of the Mage's Association Rin Toosaka and Luviagelita "Luvia" Edelfelt are entrusted with locating and retrieving seven Class Cards, medieval artifacts storing the life essence of legendary Heroic Spirits. To help them in their objective, they are given the power of Ruby and Sapphire, two sentient Kaleidosticks that allow them to turn into magical ladies and vastly improve their powers. The two magicians, however, are not on good terms, driving the Kaleidosticks to desert them in search of other masters. They come upon two young schoolgirls, Illyasviel von Einzbern and Miyu, and soon persuade them to sign a contract. Illya and Miyu set out to acquire all of the Class Cards, armed with their new abilities and duties.