D.D. halted. Her gaze ping-ponged reflexively, trying to determine the location of the intruder as the singing continued, slow and mocking: “When the wind blows, the cradle will rock . . .”

She got it then. Felt her own blood turn to ice as the full implication sank in. Why do you stage a scene? Because you’re looking for an audience. Or maybe one audience member in particular. Say, a hardworking detective stupid enough to be found after dark at a crime scene all alone.

She reached belatedly for her cell.

Just as a fresh noise registered directly behind her.

She spun. Eyes widening.

As a figure darted out of the shadows, heading straight for her.

“And when the bough breaks, the cradle will fall . . .”

Instinctively, D.D. stepped back. Except she’d forgotten about the top of the staircase. Her left foot, searching for traction, found only open space.

No! Her phone, clattering down. Her Sig Sauer, coming up. Trying belatedly to lean forward, regain her balance.

Then . . . the shadow reaching out. Herself falling back.

Down, down, down.

At the last second, D.D. squeezed the trigger. An instinctive act of self-preservation. Boom, boom, boom. Though she knew it was too little, too late.

Her head connected with the hardwood landing. A crack. A shooting pain. The final lyric, whispering through the dark:

“And down will come baby, cradle and all . . .”

Chapter 1

MY OLDER SISTER discovered my condition when I was three years old. Our foster mother walked in on her wielding the scissors, while I stood there, bare arms obediently held out, blood dripping from my wrists onto the olive-green shag carpet.

My six-year-old sister said, “Check it out, she doesn’t even care.” And slashed the scissors across my forearm. Fresh blood welled.

The woman screamed, then fainted.

I peered down at her, wondering what had happened.

After that, my sister went away. And I was taken to the hospital. There, doctors spent weeks running various tests that should’ve hurt more than my sister’s sharp-edged ministrations, except that turned out to be the point: Due to an extremely rare mutation of my SCN9A gene, I don’t feel pain. I can feel pressure. The scissors, pressing down against my skin. I can feel texture. The smoothness of the freshly sharpened blades.

But the actual sensation of my skin splitting, blood beading . . .

I don’t feel what you feel. I never have. And I never will.

• • •

AFTER SHANA CARVED UP MY ARMS with sewing shears, I didn’t see her for another twenty years. My sister spent most of that time in various institutions, gaining the distinction of being one of Massachusetts’s youngest kids ever placed on antipsychotic meds. She attempted her first murder at eleven, then succeeded at fourteen. Our own peculiar family legacy.

If she became another casualty of the system, however, then I became the state’s poster child for success.