The other valley by Howard, Scott Alexander

Sixteen-year-old Odile Ozanne is an awkward, quiet girl, but everyone knows she’s destined to land a coveted seat on the Conseil. In her apprenticeship, she competes to become one of the judges to decide who amongst the town’s residents may travel across the border. If she earns the position, she’ll decree who may be escorted deep into the woods, who may cross the border’s barbed wire fence, who may make the arduous trek over the western mountain range – or perhaps the eastern range – to descend into the next valley over. It’s the same valley, the same town. However, to the east, the town is twenty years ahead in time. To the west, it’s twenty years behind. The towns repeat in an endless sequence across the wilderness. The only border crossings permitted by the Conseil are mourning tours: furtive viewings of the dead in towns where the dead are still alive.