IN THE MORNING, when Liz’s phone alarm sounded, Jane said with what Liz suspected was feigned bleariness, “I’m going to skip the run today.” Though for all Liz knew, her sister was in the grip of morning sickness; furthermore, Liz had no idea how far into pregnancy vigorous exercise was recommended.

After using the bathroom and changing, Liz paused in the door of her childhood bedroom and looked at her sister. The curtains still were closed, but sunrise had occurred, and the room was more light than dark. Liz thought of asking if Jane needed anything, but Jane’s breathing was as deep and steady as if she really were asleep again.