In an alternate world, where the Holy Grail ritual was never completed and the Einzbern distanced themselves from the Tosakas, Illiya was able to grow up as a normal girl. Shiro is her adopted brother, Sella and Liz are her caretakers and Irisviel and Kiritsugu are mostly away on business. However, remnants from the Holy Grail ritual still remain in the form of Class Cards, the templates for the summoning ritual. Tosaka Rin and Luviagelita Edelfelt must recover the 7 Class Cards with the help of two sentient magical sticks: Ruby and Sapphire. But Rin and Luvia are more concerned with fighting each other then with completing the mission, so Ruby and Sapphire cancel their contract with them, and go looking for other girls to contract with. Ruby finds Illya, and "convinces" her to become the magical girl Prisma Illya. I absolutely love this show. It has everything I need. The soundtrack is amazing, and the fights are Fate/Zero level, sometimes above that. I recommend watching Fate/Stay Night and Fate/Zero before this, or you'll miss a lot of references, jokes and callbacks. Subs are by UTW (very slightly modified) for the episodes and my own for the specials. Also included are two untranslated drama CDs and the bluray scans which I could find.