At the age of four, Sarabeth Harcourt let her best toy, a squeaky dog named Benji, slip over the railing to Niagara Falls. The experience transformed her. She became so listless, her mother sometimes turned the lights off in a room, not realizing Sarabeth was there. At 16, Sarabeth continued to sit in the dark, indifferent even to a toothache. Her mother took her to the dentist nonetheless. There, Sarabeth saw a pale, freckly boy emerge from the dentist’s room. “The nitrous will wear off soon, Benji,” the dentist reassured him. “Okay,” the boy squeaked. Sarabeth fell tumultuously in love.