Gunpowder Empire (Crosstime Traffic, #1)

Jeremy Solter is a teenager growing up in the late 21st century. During the school year, his family lives in Southern California-but during the summer the whole family lives and works in the city of Polisso, on the frontier of the Roman Empire. Not the Roman Empire that fell centuries ago, but a Roman Empire that never fell. For we now have the technology to move between timelines, and to exploit the untapped resources of…