Margo is on a train to a new boarding school when she slips into another dimension, passing from the height of Irish summer into the chill of an alien winter, from a 24-hour day to one that begins and ends in just six hours. From a stranger on the train - a travelling salesman by the name of Moon - she learns that New Davia is part of a world scarred by uprisings, travel bans and world sealings. Power is determined by time - who has it, who doesn't, and who has the freedom to travel between time zones. Can Margo find a way to get back home - or will she choose to stay in a world where her teenagehood is slipping away faster than ever before, but where she may have found the only person with whom she would choose to spend eternity?