I just finished reading Meadowcity by Liz Delton and thoroughly enjoyed it. You can purchase the book through this link:
When she returns home to Meadowcity, Sylvia discovers that a mysterious boy has appeared at her city's gates: injured and exhausted, he collapses as soon as he steps out of the woods and sees the walled city.
As if the boy wasn't bad omen enough, the message Sylvia carries brings confusion and terror: a declaration of war from Skycity. Not one living person in all of the Four Cities has seen a war—it's something from fairytales—and nothing like it has happened in over a thousand years.
Meadowcity's Governor Gero decides to send Sylvia on a journey unlike one she has ever taken, one that will decide the fate of Meadowcity, and all of those who live in the Four Cities.
While the book is clearly the first in a series, it avoids some of the pitfalls of series books in that there is a decent story arc and no annoying cliffhanger ending. It provides enough open plotlines/questions to make me eager for the next book (no idea when that is due out, sorry) without frustrating me as a reader.
I truly enjoyed exploring the words. I guess it is odd, but the character I cared the most about was the "bad" guy. I almost wish we'd spent more time with him.
It took me a little while to figure out the time gap between the two halves of the story (one storyline takes place several years before the other) but wasn't put off by the uncertainty. The book is YA or even middle grade safe . Over all an enjoyable read.