Mara Voss, 38, is a sleep researcher at the University of Minnesota Duluth who studies other people's dreams because her own won't let her rest. She keeps a Polaroid camera for dream-journaling. One October morning there is a developed photograph on her nightstand that she did not take: a dim, unfamiliar childhood bedroom, seen from far away. Then another. Closer. The film counter confirms exposures she never made. The wallpaper - tiny blue sailboats - leads her to a 1974 fire-damage photograph, and to Eli: a boy who has been asleep for fifty-two years, waiting in a bedroom that is his mind's waiting room. To find him, Mara will have to enter it lucidly - and decide what waking him will cost.