Chaos Gate by Robert Walton

Claire walked away from her family's camp near 17th Century Strasbourg into world-changing struggles. The horror of the Thirty Years War engulfed her life when raiders from a marauding army attacked her family and the group with whom they were traveling. Though Claire escaped capture, the shock and horror of the attack froze her voice. Mere Rowan, an elderly wanderer, took Claire in, comforted her and slowly discovered what had happened to her. She discovered, too, that the girl’s troubles signaled the beginning of an invasion from other worlds. Joined by a giant bear, a hummingbird and a boy orphaned and persecuted because he is Jewish, Mere Rowan and Claire take the perilous road to Chaos Gate in hopes of healing her grief, finding her parents and preventing the invasion.