Oath-Bound — Michael Don Anderson

In Dragon's Reach: Oath-Bound (Book Four), twelve-year-old Johnny Steward is forced to help an evil brownie queen, because something dangerous and deadly is threatening their burrow. Unfortunately, Mathon, the elf-Lord cannot help rescue Johnny because the boy has been lawfully taken, thanks to an oath his father made long before Johnny was even born.

So it's up to Johnny's less than confident werewolf friend, twelve-year-old beta Ren, to enter the brownie domain and find a way to rescue the human, or else it will be war between the brownies and the elves and a slew of other races who were befriended by Johnny's father.

The problem is, what good is a single werewolf boy against the power of brownie magic? Thankfully, Ren has one surprise up his sleeve, in the form a very tiny, winged pixie named Panta. But even so, what can a boy and a couple of fairies do against a mountain full of brownies?