The Kairos Mechanism (Arcana, #1)

September, 1913. The crossroads town of Arcane, Missouri, is a place where strange things happen, and lately those strange things have a habit of happening to thirteen year-old Natalie Minks. It's Natalie who first encounters the two boys who arrive in town seemingly out of nowhere, carrying a dead man between them. Odder still, a few of her older neighbors immediately recognize the dead man as a fellow citizen who's been missing for fifty years--and who doesn't appear to have aged in all that time. When another newcomer, a peddler called Trigemine, arrives in town, Natalie learns why the two boys and the peddler have really come to Arcane. And, of course, she realizes she has to stop them.