When she was ten, Sophie had wanted to be Florence Nightingale for Halloween. She'd done meticulous research, knew exactly what her costume should look like down to the exact lamp she planned to carry and she could even recite the Nightingale pledge.

Her sister put her foot down. "No. You're going to want to recite that stupid oath."

"Pledge," Sophie said.

"At every single house," her sister continued as if Sophie hadn't even spoken. "Then you'll spend ten minutes going on and on about the great nurse and we'll hardly get any candy at all."

Less candy? Surprised to realize her sister actually did have a point, Sophie understood, for the first time, that you had to pretend to be somebody else to get what you wanted.