Where's Glimmer?

"Now that Princess Bella has officially been matched with her sparkly unicorn, Glimmer, it's time to show her off to the entire Crystal Kingdom! Bella is tickled purple that she finally has a unicorn to call her own. But when Bella goes to take Glimmer out for her very first ride, Glimmer's stall is empty! Where did Glimmer go? And why would she run away? It is up to Bella, with the help of her BFFS, Ivy, Clara, and their new friend, Ben, to find out, even if it means searching every inch of Crystal Kindom. Including the super-scary Dark Forest..."--Book jacket.