“Nature versus nurture. You received the advantage of a caring home, versus your sister, who remained in the foster system. Hence, you’re about to attend one of the most prestigious medical schools in Boston; whereas, your sister remains forever chained to the school of hard knocks.”

“That’s cruel.”

“And you’re lying to yourself, Adeline. This has nothing to do with nature versus nurture. It’s survivor’s guilt, pure and simple.”

“She’s my sister—”

“Who has a long history of committing acts of violence against others, not to mention yourself. Adeline, give me one good reason to choose Shana as family. One good reason, and I’ll let it go.”

I thinned my lips mutinously, looking away. “Because,” I muttered.

My father threw his hands up in the air. “God save me from know-it-all college students. Tell me, have you sent her money?”

More silence. A second fatherly sigh.

“She asked, didn’t she? Why not? She’s a master manipulator and you’re an easy target. She’s locked in the big house, and you’re living in one.”

“Or maybe she’s my older sister and I’m her little sister and this is the way sisters have always been.”

“Nice sentiment. She write that?”

“I’m not naive!”

“Fine. Stop sending her money. See how long before the letters dry up.”

“She wants to know me.”

“And you?” My father, for the first time sounding less certain.

“I’m . . . curious. We both know my dad is infamous.” I heard myself recite: “The sick and twisted Harry Day just wanted to find a good lay. Grab ’em, stab ’em, whack ’em, hack ’em. He told each one he loved her best. Then buried her bones with all the rest.”

I’d heard the rhyme for the first time in middle school. I’d never told my adoptive father, though. Because sometimes pain is knowing, and sometimes pain is sharing that knowledge with someone who loves you but can’t do anything to help.

My father’s shoulders came down. His brown eyes were kind. “True.”

“My sister, too. Right? I come from a family of killers.”

“Yes,” he agreed somberly. “That is your gene pool.”

“And despite what we would like to think, nature is a major factor in psychological behavior. Love alone cannot change the world.”

“You are too young to sound so cynical, my dear.”

I continued, “I don’t think I’m a killer.”

“Thank heavens.”

“But I think I should know what I don’t know, study what I can’t remember. Because my birth family is my legacy and you always taught me there’s nothing to be learned from denial. Confront, analyze, master—isn’t that what you recommend?”