Always looking for an adventure, Prince Marcus asks Gracie Gillypot to join him in some dwarf spotting, but their journey into the Unreliable Forest goes horribly wrong when Gracie disappears. Underground, the dwarves have struck a dangerous bargain with the King of the Trolls, and Dreghorn's balance of power, held in a mysterious heart of glass, could change forever. Can the heroic Prince Marcus save both Princess Marigold and Gracie from the grips of a lonely troll and a scheming goblin? A Junior Library Guild Selection