In the fourth book of USA Today bestselling author Rebecca Elliott's Unicorn Diaries series, unicorn best friends Bo and Sunny try to cheer up Greta, a bored goblin princess. But Greta wants to do more than just play games-she wants to fly! So Bo grants Greta's wish and gives her magical Goblin Queen Powers. But as things start to get out of HOOF, can the unicorns find a way to clean up Greta's messes-and show her the power of imagination? With full-color artwork throughout and plenty of laughs, your young reader won't be able to put this book down!