No True Echo by Gareth P. Jones
Hot Key Books
Eddie is pretty certain nowhere could be more small-town, more boring, and more inconsequential than his home town of the Wellcome Valley. Unfortunately, he is about to be proved spectacularly wrong. Eddie's problems start with the arrival of Scarlett, a new girl in town who seems rather too confident and mysterious for your average schoolgirl.
She attracts trouble (and Eddie) like a magnet, and she's apparently only interested in two very strange things - protecting the town's local crackpot scientist, and telling Eddie absolutely nothing about what on earth is going on. And why is she so interested in Eddie's long-dead mother? Things quickly go from weird to worse for Eddie, as he finds himself right in the middle of a dangerous mystery - one with consequences not just for him and Scarlett, but time itself.