One day, while searching the library of the Castle of Two Sisters, Twilight finds a rather unusual book in the reserved section. It is a children's book of sorts, looking as if it were misplaced. It tells of a tale of a young mare, Arcega Shutts Minn, setting out on a quest to save her kingdom alongside her four friends. Twilight becomes obsessed with it, not stopping until she reaches the end, almost concerning her friends. Could this book perhaps contain something sinister, or is it all in the mind?