Bo grants the goblin princess a wish in this magical early chapter book from the USA Today bestselling author of Owl Diaries! 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?