Stealing the Dark Moon: Dragon's Den Orphanage Volume I

How far would go to protect your dragon? A boy must betray the dragon that gave him a true home and family in order to save his guardian's life. Fourteen-year-old Foxkit plays with fire by striking a bargain with the ferocious dragon Aerohim: Let six runaway orphans hide in his den in Galefang forest, and they will help him find a lost artifact in his vast treasure hoard. Yet the longer they search, the more Kit hopes they'll never find it as the dragon's den becomes the home he never had. 

Kit's wish is threatened when Aerohim starts growing weaker by the day, and the mysterious magic tracker Sheen warns him that their dragon is dying. She promises to heal Aerohim in exchange for one little thing from the hoard—the Dark Moon, a talon that once belonged to the powerful ancestor of all dragons. But Sheen isn't the only one hunting that ancient relic. Lord Ash, a fallen unicorn that harvests magic bones from other creatures to replace his broken horn, storms the Galefang. 

Not wanting harm to come to the only one that has ever treated him like family, Kit must decide whether or not to steal the Dark Moon. Steal it, and lose Aerohim's trust forever—but just maybe save his life.