THE SERUM WEARS off five hours later, when the sun is just beginning to set. Tobias shut me in my room for the rest of the day, checking on me every hour. This time when he comes in, I am sitting on the bed, glaring at the wall. “Thank God,” he says, pressing his forehead to the door. “I was beginning to think it would never wear off and I would have to leave you here to … smell flowers, or whatever you wanted to do while you were on that stuff.