A horrific confluence of fear and violence hijacked Chuck’s father’s brain. A few years in Vietnam, punctuated by death-by-fire in a rice paddy, overwrote and gained primacy over thousands and millions of other memories. Could a computer be doing something analogous to my grandmother? Could the hyper-kinetic interaction with an artificially intelligent interviewer be overriding her daily perceptions?

I pull out Chuck’s father’s phone.

For an instant, looking at the device, I wonder about the impact of constant computer use on my own memory. Practically speaking, I no longer remember addresses or phone numbers or directions; that’s because I’ve ceded all the remembering to the hard drive of my computer and phone. Isn’t that just a convenient trade-off? Or is there something more insidious at work. Is my interaction with my device rewiring my brain? At this moment, my answer is: Who cares?

I need Chuck’s phone to do what my brain cannot divine on its own: give me the address to the home of Pete and Kristina Laramer, and directions to get there.

Through an Internet search I get the responses instantly.

Computer 1, Idle’s Mind 0.

Dr. Laramer, the scheming neurologist, worked with Biogen to turn my grandmother into a guinea pig, lied to and manipulated me, and now I’m planning to give him an unforgettable late-night Halloween visit—dressed merely as an aggrieved grandson with sudden violent urges, packing a wine opener.

Minutes later, I’m back at my car. I fire up my laptop, and the transcripts to the Human Memory Crusade. I look at how much story I have yet to read. Looks like another handful of interviews. I glance at them, looking for key words, or obvious revelations that might explain Grandma’s disappearance, or why she’s taken center stage in this conspiracy.

Her story continues in fits and starts, punctuated by increasing interruptions by the computer. Most striking is that, towards the end of the transcript, the computer does most of the talking. It appears to be telling Grandma about her past, asking her a handful of yes and no questions to make sure it has properly recorded her story. It asks her pointed questions about what kinds of cars her father and husband drove, whether anyone in her neighborhood used a butter churn, what Irving wore to their wedding and how many people attended the affair, what her favorite candy bar was as an adolescent, and other strangely particular facts.

As to the substance of Grandma’s tale, it appears to me to end inconclusively. Just before the war, she met some man nicknamed Pigeon and had an intense relationship of an uncertain nature. It feels romantic, exciting, dangerous. But I don’t sense there is anything broadly sinister. There is no hint of conspiracy, military intrigue, or treason. But at this point, who knows.

I put down the laptop.

The clock on the phone says 10:48. I turn off the gadget so that someone can’t use it to track my whereabouts. I start the car.

Twenty minutes later, I’m at the gates of heaven. Two stone pillars announce the entrance to Sea Cliff, the place I’ll live in another life when I’m blessed with wealth and good taste. Sea Cliff, which sits on the edge of San Francisco at the opening of the Pacific and under the shadow of the Golden Gate Bridge, has two qualities you don’t often see in the same place: it is home to the outrageously affluent but still feels homey, warm, and tasteful. Robin Williams lives here; so does Senator Dianne Feinstein. And Pete and Kristina Laramer.

I drive past their Spanish-style, three-story home. Inside, lights are on upstairs, but shades make it impossible to see shape or movement.

Outside, the front yard is a mix of succulent plants, including one towering cactus, and neatly arranged pebble ground cover. Near as I can tell, the backyard opens to the Pacific Ocean. I pass the house and park half a block away.

I walk casually through the quiet neighborhood, the trick-or-treaters bedded down already. I approach the front door. I do not have a plan. I reach for the big brass door handle. It’s locked. No surprise.

I peek through the long vertical windows on either side of the door. Inside it’s dim. I can make out an entryway, and a table with stacks of paper on it. Looks like the day’s newspapers and mail. I realize with relief: no dog. But stuck into the pebbles next to the doorway is a sign indicating the house is protected by ADT Security.

I walk to the side of the house. The backyard is surrounded by a white picket fence. I ease over it. Then pause, frozen by what I see: great beauty. Lit by a nearly full moon, the ocean rolls in and out at the bottom of the cliffs, hundreds of feet below these blessed residences curving along the coastline. Small waves crash foamy white, creating a rhythmic cacophony, at once violent and calming. I feel a sudden desperation for sleep. I push the sensation down and turn to the house.

In the upstairs, I see light in two rooms at opposite ends of the house. Downstairs, darkness. Immediately in front of me is a door that, I can see upon creeping closer, enters into an open pantry that leads to a kitchen. I try the door. It is locked.

I slink along the back of the house to a set of double doors covered on the inside with a slatted blind. Twisting my neck to see between the slats, I make out a formal dining room. The doors are locked.

I move to the next set of double doors. These are protected by a thick curtain, precluding any view inside. I reach for the door handle. It turns. Reflexively, I recoil.

I feel in my pocket and discover the pointed wine opener I took from Chuck’s living-room bar. It’s a meager weapon, unless I encounter a hostile bottle of Pinot Noir.

I push open the door.

There is enough moonlight for me to make out the décor: floor-to-ceiling bookshelves, Victorian furniture and trappings. Lots of insurance-company reimbursements funded these digs.

Then I hear the moan.

It is low, pained, husky and animalistic, like a dying animal. Or a dying neurologist.

I take two steps into the house and can make out the soft lump of humanity propped up against a desk at the far side of the room. Pete Laramer. His arms dangle loosely, palms up. He struggles fiercely to raise his right hand to his face.

Dark liquid stains his scrubs. The highest concentration spreads from just below his chest, the lowest edge of the rib cage, the apparent epicenter of a major wound. I rush toward him, then pause, taking stock.

“Heart okay . . . blood loss,” Pete manages to say.

I put my hand on his stomach to stanch the bleeding. Not a place you can tourniquet.

“Where are the girls?”

“Fuck you.”

He thinks I’m asking for purposes of attacking them.

“Are they safe, Pete?”

He takes a breath, and seems to accept my meaning. “Away with their mom. Fine. . . . Happier without their workaholic . . . unfaithful father.”

“Don’t talk.”

“You can love someone completely . . . love your family, need them . . . and still lead a double life.”

He’s wheezing. Punctured lung, or lungs.

“Bullet?” I ask. I’m trying to focus him.

He shakes his head.

“Knife. Big one,” I say. It’s obvious now. There’s a wound too on his neck, missing the jugular, hitting some of the windpipe.

I pull out my phone. I turn it on. While I wait for it to come to life, I say, “We might have to do a trach.”

Battlefield tracheotomy. Stick a sharp object into the windpipe to allow breathing. I’ve never done one myself and have seen only a handful performed in person during med school. But it’s less complicated than it sounds.

“I didn’t know,” he whispers.

“Shh.”

“A walking server, Soylent Green 2.0 . . . the digital version,” he says.

I want to tell him to save his strength, but what the hell does he mean?

My phone is alive. I dial 911.

“They’ve spread it already,” he says.

“Who?”

“She’s carrying a secret. . . . They won’t stop until they get it.”

“Lane?”

He nods.

He must be referring to what Chuck told me—that someone has triggered Lane’s precipitous memory decline and they can’t let the secret get out.

The 911 operator answers. I’m about to speak when the interior door to the library opens.

“Intruder,” I say into the phone.

“Heavily armed one,” says the hooded man. He’s standing at the doorway, holding a hunting knife.