Serena slowly awoke from a deep, dreamless sleep and realized her situation. She was lying on Nathan's shoulder, and to her surprise, he too had leaned his head against hers in an unexpected gesture of weariness. They had both fallen asleep, overcome by the exhaustion of the long drive. When she noticed that the car had come to a stop, she looked out and realized that they must have arrived in Great Falls, Montana, at their first stop, a hotel that Nathan had chosen for the day. Nathan was planning to visit a friendly pack here on their way to Vermont.

Nathan woke up shortly after Serena. Unlike her, who...