From The Book of Atlantis Black, which was published last month by Tin House Books.

1.

Once, when my older sister Nancy was twelve, she told me she’d decided to run away by hopping a freight train. Her best friend, Jen, had done it. When she invited me to join her, I refused, and threatened to tell our father.

“Don’t be a wuss,” she said. She stared me down and ordered me not to say anything to anyone, even if she never came back.

She was gone for several hours. Mom had a doctor’s appointment that day but…