How do people decide on a path, and find the drive to pursue what they want? Ida struggles more than other twentysomethings to work this out. She can shift between parallel universes, allowing her to follow alternative paths.One day Ida sees a shadowy, see-through doppelganger of herself on the train. She starts to wonder if she's actually in control of her ability, and whether there are effects far beyond what she's considered. How can she know,...