For months, a master thief known as 'The Shade of Canterlot', has been stealing priceless artifacts leaving behind not a single clue other than his personal calling card. With the Royal Guard stumped and the thief still not apprehended, Princess Celestia will assign her faithful student, Princess Twilight Sparkle, to the case. However, she will not be alone. Her partner may in fact prove to be an even greater challenge to deal with than the thief at large.