Once they got going again, Kylie and Ethan took the lead and, eventually, they came to a fork in the road. Kylie looked back, and then her eyes strayed down each path. They hadn’t seen Stephen and Dinah for a long time, but they arranged in advance which way they would go in advance, so she was surprised to see that Ethan went the wrong way. “You’re going the wrong way,” she said.

“We’re not going the same way as they are,” he replied. “We’re going to watch the ...