“Hello,” he said, his voice thick and dry.

“Dr. Hobson?” said a man’s voice.

“Yes.’

“This is Sepp van der Linde at Carlson’s Chronic Care. I’m the head night nurse.”

“Yes?” Peter fumbled for a drinking glass and filled it from the tap.

“I think Mrs. Fennell is going to pass on tonight. She’s had another stroke.”

Peter felt a small twang of sadness. “Thank you for letting me know. Is my equipment all set up still?”

“Yes, sir, it is, but—”

He fought to stifle a yawn. “Then I’ll come by in the morning to pick up the data disk.”

“But Dr. Hobson, she’s asking for you to come.”

“Me?” said Peter.

“She said you’re her only friend.”

“I’m on my way.”

Peter arrived at the chronic-care facility about 4:00 a.m. He showed his pass to the security guard and took the elevator to the third floor. The door to Mrs. Fennell’s room was open and the incandescent light directly above her head was on, although the main overhead fluorescents were out. A row of four green LEDs pierced the gloom beside the bed, showing that Peter’s equipment was working properly. A nurse sat on a chair next to the bed, a bored look on her face.

“I’m Peter Hobson,” Peter said. “How is she?”

Mrs. Fennell stirred slightly. “Pe-ter,” she said, but the effort of even those two syllables seemed to visibly weaken her.

The nurse got up and moved over to stand next to Peter. “She had a stroke about an hour ago, and Dr. Chong expects she’ll have another one shortly; there are several clots in the arteries feeding her brain. We offered her something for the pain, but she said no.”

Peter stepped over to his recording unit and turned on the screen, which immediately came to life. A series of jagged lines traced from left to right. “Thank you,” he said. “I’ll stay with her. You can go now, if you like.”

The nurse nodded and left. Peter sat in the chair, the vinyl back warm from the nurse. He reached out and took Mrs. Fennell’s left hand. There was a catheter inserted into the back of it, a tube leading to a drip bag mounted just beside the chair. Her hand was thin, small bones covered by translucent skin. Peter encircled Mrs. Fennell’s fingers with his own. She squeezed his hand very softly.

“I’ll stay with you, Mrs. Fennell,” said Peter.

“P— P—”

Peter smiled. “That’s right, Mrs. Fennell; it’s me, Peter.”

She shook her head ever so slightly. “P— P—,” she said again, and then, with great effort, “Peg—”

“Oh, that’s right,” said Peter. “I’ll stay with you, Peggy.”

The old woman smiled ever so slightly, her mouth just another line across her face. And then, without any fuss, her fingers went limp in Peter’s hand and her eyelids slid very slowly shut. On the monitor, the green tracings had turned into a series of perfectly straight horizontal lines. After several moments, Peter retrieved his hand, blinked slowly a few times, and went to find the nurse.

Peter took the superEEG recording with him when he left the chronic-care facility. By the time he got home, Cathy was getting ready for work, nibbling at a piece of dry whole-wheat toast and sipping a cup of tea. He’d left her a message with the household computer, so she’d know where he was.

“How did it go?” asked Cathy.

“I got the recording,” said Peter.

“You don’t seem very happy.”

“Well, a very nice lady died tonight.”

Cathy looked compassionate. She nodded.

“I’m exhausted,” said Peter. “I’m going back to bed.” He gave her a quick kiss, and did just that.

Four hours later Peter woke up with a headache. He stumbled to the bathroom, where he shaved and showered. He then filled a large tumbler with Diet Coke, got the disk, and went to his study.

His home system was more powerful than the mainframe he’d had to share access to as a student at university. He turned it on, inserted the disk into the drive, and activated the wall monitor on the other side of the room. Peter wanted to see the moment at which the last neuron had fired, the moment at which the last synapse had been made. The moment of death.

He selected a graphic display mode and played a few seconds of the data, having the computer plot every location at which a neuron had fired. Not surprisingly, the image on the screen looked exactly like a silhouette of a human brain. Peter used an edge-tracing tool to draw the outline of Mrs. Fennell’s brain. There was enough data to generate the picture three dimensionally; Peter rotated the image until the brain silhouette was facing him directly, as if he was looking the late Mrs. Fennell straight in the optic nerves.

He let the data play in real time. The computer looked for patterns in the firing neurons. Any connected series that fired once was color-coded red; twice, orange; three times, yellow; and so on through the seven colors of the spectrum. The picture of the brain looked mostly white: the combined effect of all the different colors of tiny dots. Peter occasionally zoomed in to see a close-up of one section of the brain, lit up with strings of infinitesimal Christmas lights.

As he watched, he could clearly see the stroke that had proved the final straw for Peggy Fennell. The color-coding scheme was refreshed every tenth of a second, but soon an area of blackness began to grow in her left temporal lobe, just below the Sylvian fissure. It was followed by an increase in activity, with the whole brain growing brighter and brighter as disinhibition caused neurons to fire again immediately after they’d last fired. After several moments, a complex network of purple lights was visible throughout her brain, a whole series of neural nets being triggered in identical patterns over and over as her brain spasmed. Then the nets began to fade, and no new ones replaced them. After ninety years of service, Peggy Fennell’s brain was giving up the ghost.

Peter had hoped to be able to watch it all dispassionately. It was just data, after all. But it was also Peggy, that brave and cheerful woman who had faced and beaten death once before, that woman who had held his hand as she passed from life into lifelessness.

The data continued to be plotted, and soon there were only a few patterns of light, like constellations on a foggy night, flickering on the screen. When the activity did stop, it did so without any apparent flourish. Not a bang. Not a whimper. Just nothingness.

Except…

What was that?

A tiny flash on the screen.

Peter reversed the recording, then played it back again at a much slower speed.

There was a minuscule pattern of purple lights — a persistent pattern, a pattern that kept firing over and over again.

And it was moving.

Neurons couldn’t really move, of course. They were physical entities. But the recorder was picking up the same pattern over and over again, just slightly displaced to the right each time. The recorder allowed for such displacements: neurons didn’t always fire in exactly the same way, and the brain was gelatinous enough that movements of the head and the pulsing of blood could slightly change the physical coordinates of a neuron. The pattern moving across the screen must have been propagating from neuron to adjacent neuron in steps small enough that the recorder mistook the individual increments for activity within the same neurons. Peter glanced at the scale bar at the bottom of the wall screen. The violet pattern, a complex knot like intestines made of neon tubes, had already shifted five millimeters, far more than any neuron could move within the brain except in the case of a major blow to the head, something Peggy Fennell had most assuredly not suffered.

Peter adjusted a control. The playback speeded up.

No doubt about it: the knot of violet pinpricks was moving to the right, pretty much in a straight line. It rotated a bit as it moved, like a tumbleweed blown by a desert wind. Peter stared in openmouthed wonder. It continued to move, passing over the corpus callosum into the other hemisphere, past the hypothalamus, and into the right temporal lobe.