Meribabell and the Undead Trolls

Why would the High Fairy send Meribabell, a young know-it-all fairy, after a runaway renegade? Something strange is going on out on the frontier of the Faerie Kingdom, and Meribabell runs smack dab into it, collecting friends and enemies along the way. Everyone gets more than they expected.
Can anyone say - dwarves, elves, pixies, trolls and a wizard? And, oh yes, humans, too.