My mother retreated into herself. Though she did not speak of it, it was clear to me that her thoughts never wavered from what had happened. I could see questions and theories spinning behind her distant gaze. Sometimes I overheard her speaking to herself: “I know it. I know it.” In books and movies, the bedrooms of dead children become temples—untouched, everything preserved just as they left it. But my mother lived in Alison’s room. I would return from school to a silent house and know she was in there, curled up in Alison’s sheets. One day I opened the bedroom door to find her sitting at Alison’s desk, cupping something in her hands. It was a nest of Alison’s hair, pulled from her yellow brush.

For my part, if before Alison’s death I had been prone to some mildly compulsive behavior, in the aftermath this spiraled into a genuine affliction. I felt the prickling in my fingertips, the need to write in the air, constantly. Alison. Alison. Alison. I also developed a second, intertwined compulsion of thinking up scenarios in which those I loved might die. It was a ritual of protection: If I imagined a specific death, it seemed nearly impossible that it would actually happen in exactly that way, so the more scenarios I imagined, the safer the people I loved became. After my mother tucked me in at night I lay awake for hours, tracing Alison’s name while conjuring visions of my parents lying in parallel hospital beds succumbing to a rare infection, of our dog Fluffernutter crushed by a falling tree limb, and crying because I was exhausted and desperate for sleep and my powerlessness in the face of these rituals terrified me. I wanted to wake my parents but knew I mustn’t add to their worries. I faced the long night hours alone, until the sky began to lighten and, my night’s watch completed, my mind finally released me to sleep.

DEPENDING ON where you lived then, maybe you remember how brutal the winters were in the mid-nineties, how the Eastern Seaboard bore nor’easter after nor’easter from December straight through April. During those winters, a good number of Americans found themselves stuck inside for months on end, huddled around televisions and desperate to be entertained. If you were one of them, you will remember how Alison was all over the news the winter she was killed, as Nancy and Tonya and JonBenét were during other winters around that time. It seemed the national appetite craved—demanded, even—a dramatic story about an American beauty. (Nancy in all those crystals, glittering across the Lillehammer ice. JonBenét the way I loved her best, sans makeup, as my mother would say, her natural brown hair waving out of a cowboy hat, a red bandana around her slender neck.) News vans loitered on our suburban cul-de-sac for weeks. I was forbidden from playing in the front yard. But one day I disobeyed this rule. It had snowed the night before. While my parents were still asleep, I put on my snow pants and my puffy purple jacket and slipped out the front door. I clomped through the knee-deep snow, lay down on my back, and fanned my arms and legs back and forth. I looked up at the sky. It was white, but the color didn’t seem to reside anywhere. It was like the turquoise in the water at Indigo Bay, colors that were everywhere and nowhere. Had my sister slid into the infinity between color and object? Was she out there, in some incomprehensible elsewhere, watching me? Inside my mittens, my hands worked furiously. Alison. Alison. Alison.

A few minutes later my father opened the door and shooed me inside. That night, my mother was draining pasta for dinner with the small white television in the kitchen tuned to the local station, when there I was, swishing my arms and legs through the snow. “The search for answers in the death of local teen Alison Thomas continues,” a woman in a magenta blazer said. “Meanwhile, on this snowy day, her sister could be seen making angels.”

IN APRIL, the chief of police on Saint X called our house. We had just sat down to dinner. My father answered the call on the phone that hung on the wall beside the stove, and I watched as he listened, twisting and untwisting the cord. The chief of police had called to inform him in advance that he would be holding a press conference the next day, at which he would announce that all suspects in my sister’s case had been cleared, and the department had concluded there was not sufficient evidence that Alison had died as the result of a violent crime to continue the investigation.

My father flew into a rage. I don’t remember what he said, but I do remember his shouting, and how I looked down at the drumstick and green beans on my plate like maybe if only I stared hard enough it would all go away—this moment and all the others since I had awoken to find my sister gone. When my father’s shouts became choked with sobs I thought I would be sick. I began to trace Alison’s name furiously on the kitchen table.

“Stop that, Clairey,” my mother said.

I wanted so badly to stop for her, but I couldn’t. My eyes filled with tears. She put her hand over mine, but I shook it off. I cried harder, pressed my fingertip against the tabletop so hard it hurt.

“Clairey, please,” she begged.

My body began to tremble.

Then my mother knelt next to my chair and looked straight at me. For the first time in months her eyes seemed animated not by some scene playing out in her mind, but by the present we shared. Though I was much too old to be carried, she lifted my tensed body out of the chair. I let myself go slack in her arms, and she carried me upstairs and tucked me into bed. She stayed there with me, stroking my hair, until I was asleep.

A FEW weeks later, my parents surprised me with the news that my Aunt Caroline would be taking me to Paris. A present for my eighth birthday, they said. Aunt Caroline was my mother’s older sister. She had never married and had no children. She lived in the East Village and was the only adult I knew who smoked. For a week she and I shared a little chambre in the Marais. Every morning we had bread with butter and raspberry jam and espresso at a café in the Place des Vosges. (“See how butter tastes like butter here,” Aunt Caroline said.) I forced the espresso down, trying to convince myself I liked its sophisticated intensity. We did not go to the Eiffel Tower or Versailles, nor to any of the kid-friendly attractions my parents would have sought out: wax museums, puppet shows. We did what Aunt Caroline called “being flaneuses.” We wandered. If we passed a fromagerie with logs of goat cheese pressed with lavender in the window, we bought some. We ate long leisurely dinners during which Aunt Caroline drained carafes of plum-dark wine. We lazed in parks all afternoon.

Alison had never been to Paris. I had nibbled a brioche aux pralines in the Luxembourg Gardens and she never would. I would have this on her forever. I would have every day on her for the rest of my life. In Paris with Aunt Caroline, I finally began to understand that my sister was not gone the way she’d been gone when she was off at college—vanished from my days but still out there, living her life. She was gone not just from me and my parents and Drew McNamara, but also and above all from herself. My parents’ grief might lessen, I might heal, Drew might move on, but Alison’s loss—of a future, a life—would never change.

On the plane back over the Atlantic, Aunt Caroline slept with her mouth snapped open like a crocodile’s for seven straight hours. I remained awake. I was anxious about returning home. I was wary of my father and even more so of my mother—how when I got home she would squeeze me in her arms so tightly I would be able to feel her thinly veiled terror that I, too, might vanish.

But when my parents met us at the airport, my mother’s smile was light and clean. She’d gotten a haircut. My whole life her hair had come down past her shoulders; now it barely skimmed her chin. She was wearing a blue chambray dress and sandals.

“Did you have the very best time?” she asked.

Things were different after that. My father went back to work. If he continued to be in contact with the police on Saint X, he kept it to himself. When I got home from school in the afternoons, my mother was no longer in Alison’s room; she was waiting for me in the kitchen with a glass of milk and a plate of Oreos. Always a voracious reader, she began to check out books from the library again. My father rejoined his Sunday squash game. At night from my bedroom I sometimes caught the faint sound of a laugh track—they were watching Murphy Brown in bed.

Every so often in the years that followed, my parents received a briefing from the police. A former maid at Indigo Bay had remembered something that might turn out to be consequential. A man from Chicago had called with a tip that seemed bogus, but which the police would of course pursue with diligence and expediency. My parents did not fixate on these developments, and in the end none of them ever amounted to anything.

When someone asked my mother how many children she had, her response was always the same. “We had two daughters but our eldest was killed.”