2. Null Protocol

The message from NullHyatt sat on Lott's tablet like a spider in the center of a web. She read it five times, then set the device face-down on her desk and walked to the window. The rain had not stopped. It had become a permanent condition, a second atmosphere, and the city of Port Fergus seemed to be slowly forgetting what dry ground felt like. Gutters choked. Drains failed. The river Clyde, swollen and brown, gnawed at the embankment with a hunger that was almost personal.

“He knew my name,” Lott said to the rain-streaked glass. “He knew I was on the case before the case existed.”

Malone stood in the doorway, his coat still dripping. “We need to secure our systems. If he can read our emails—”

“He can read everything.” Lott turned. “He's not some basement hacker, Ryan. He built this grid. He wrote the protocols. And he's had eighteen months with nothing to do but prepare.”

She walked back to her desk and picked up the tablet. The post was still there, glowing with the quiet menace of a thing that should not exist. You're not hunting me. You're reading my CV. She had known killers who taunted the police before. She had never known one who could watch them through the very devices they used to hunt him.

“Call Cyril,” she said. “Tell him to stop what he's doing and run a full vulnerability audit on every system the Major Crime Unit touches. Phones, tablets, the incident database, the traffic camera network. If there's a backdoor, Hyatt installed it years ago and we've been using it ever since.”

Malone nodded and left. Lott sat down and opened the Hyatt file again, spreading the documents across her desk in a chronological map of destruction. The initial accident. The denied claim. The appeal. The fire. And now, nine years after the transformer explosion at Croy substation, a series of deaths that followed the exact chain of bureaucratic responsibility.

Aileen Draper, the medical consultant who had spent twenty minutes assessing a paralysed man and declared him capable of work. Dead from a pacemaker malfunction, her heart stopped by a command that may have travelled halfway around the world.

Gerald Koskinen, the regional director who had signed the denial letter with the word “unfortunately” and a rubber stamp. Electrocuted by a light switch that had been patiently waiting to kill him for three days before he touched it.

Marcus Venn, the claims adjudicator who had written a twelve-page rejection letter and used the word “unfortunately” eight times. Scalded to death by a shower that had been programmed to execute him.

Lott was not a technologist. She had grown up in an era when murder meant proximity—a killer had to be close enough to touch, to strike, to leave behind the messy physical evidence of his presence. But Hyatt had turned murder into a distributed system. He was killing people without ever being in the same room, the same street, the same city. He was a null pointer that resolved to death.

Her phone rang. Cyril Abasi's name flashed on the screen.

“I got into the forum,” Abasi said. His voice was tight, compressed by the kind of excitement that was indistinguishable from fear. “MirroredCatacomb. The encryption was tough, but they had a vulnerability in their handshake protocol. Once I was in, I found something. Something big.”

“Tell me.”

“NullHyatt isn't just posting manifestos. He's been distributing code. Open-source malware designed to target smart-home systems, industrial control units, municipal SCADA networks. He calls it Null Protocol. Anyone can download it. Anyone can use it.”

Lott felt a cold hand close around her spine. “He's weaponising the public.”

“That's not the worst part,” Abasi said. “The forum has a user base of about sixty thousand. They're not all active, but the thread where Null Protocol was posted has been viewed over two hundred thousand times. The comments section is full of people thanking him, asking for technical support, sharing their own modifications. There's a whole community of them. They call themselves Nullers.”

“What are they saying?”

“Some of them are just angry. People who've been denied benefits, people who've lost loved ones to the system, people who hate the Federal Security Agency. But there's a hard core that's been testing the code. I found logs from at least a dozen installations. Water heaters. Traffic light controllers. Elevator systems. None of them have been triggered yet, but the capability is there. It's like an arsenal waiting for a match.”

Lott closed her eyes. Port Fergus had half a million residents. Half a million homes. Half a million showers, light switches, traffic lights, pacemakers. And somewhere in the digital darkness, a community of the disenfranchised was learning how to turn ordinary infrastructure into instruments of execution.

“I need names,” she said. “I need locations. I need to know which of these Nullers are in Port Fergus and which of them have accessed the city's grid.”

“That's the problem,” Abasi said. “The forum is anonymised. Every user is behind multiple layers of encryption and routing. I can read the posts, but I can't trace the posters. Not without access to the server itself, and the server is probably in a jurisdiction that doesn't cooperate with extradition.”

“Then find me the server. Or find me another way in.”

She hung up and stared at the whiteboard. Three names. Three deaths. And now a fourth name: NullHyatt, which was not a person but a distributed identity, a ghost that inhabited the network itself.

Malone returned with a laptop open in his hands. “Cyril's running the audit. But we've got another problem. The media got wind of Venn's death. Some reporter at the Port Fergus Courier put together a timeline of the three FSA deaths, and now it's trending on social media. The commissioner wants a press conference at noon.”

Lott swore under her breath. “The commissioner doesn't know what we're dealing with.”

“Nobody does. That's the point.” Malone set the laptop on her desk. “There's something else. I pulled the visitor logs for Vectis Water and Power's central control room. Three weeks before Aileen Draper died, someone logged in using a retired employee's credentials. The credentials belonged to a shift supervisor who died of a stroke two years ago. The access lasted seventeen minutes and involved a full download of the municipal water distribution map.”

“Hyatt's using dead men's passwords,” Lott said. “Of course he is. He's a dead man himself.”

She stood and pulled on her coat. “I need to talk to his ex-wife.”

Elise Carrick lived in a pebble-dashed semi-detached house on the edge of Campsie, a former mining village that had been swallowed by Port Fergus's suburban sprawl. The front garden was tidy, with a child's bicycle propped against the wall and a row of terracotta pots filled with winter-bare rose bushes. Lott parked on the street and walked up the path through a drizzle that had finally thinned to something almost gentle.

The woman who opened the door was in her early forties, with greying hair pulled back in a severe ponytail and the kind of watchful stillness that came from years of being told she was wrong. She looked at Lott's warrant card and her expression did not change.

“You're the one who called,” she said. “About Aaron.”

“I need to ask you some questions, Ms. Carrick. May I come in?”

Elise Carrick stepped aside. The house smelled of toast and laundry detergent. Through an open door, Lott could see a living room with a piano against one wall and a framed photograph on the mantelpiece—a girl of about twelve, dark-haired and serious, holding a swimming trophy.

“My daughter's at school,” Carrick said, following Lott's gaze. “She doesn't know anything about this. I'd like to keep it that way.”

“I understand.” Lott sat on the edge of a sofa that had seen better decades. “Tell me about the fire.”

Carrick sat opposite her, her hands folded in her lap. “I told the Procurator Fiscal everything three times. They didn't listen. Why would you?”

“Because three people are dead who were involved in your ex-husband's case. Because I found evidence that his death was staged. And because someone using his name has been posting on an encrypted forum, claiming credit for the killings.”

Carrick's composure cracked, just for a moment. Something flickered in her eyes—fear, or hope, or some emotion that had no name. “You think he's alive.”

“I think someone is alive who knows everything Aaron Hyatt knew. Someone who has his technical expertise, his passwords, his memories. Someone who had eighteen months to plan a war against the Federal Security Agency.”

Carrick looked away, toward the window and the grey rain. “Aaron was the smartest person I ever met. When the accident happened, he said the only thing worse than being paralysed was being patronised. He said the system didn't treat him like a person anymore. He was a file. A case number. A cost to be minimised.”

“Is there anyone who might have helped him? Anyone with the technical skills to stage a death and then mount an infrastructure attack?”

Carrick was silent for a long moment. Then she said, “There was someone. A man named Saul Drummond. He and Aaron worked together at Vectis. They were close—closer than colleagues, really. Saul was the one who found Aaron after the explosion. He stayed with him through the rehabilitation, through the appeal, through everything. When the claim was denied, Saul was angrier than Aaron was. He said the FSA was going to pay for what it did.”

Lott felt the name settle into her mind like a key turning in a lock. “Where is Drummond now?”

“I don't know. After the fire, he disappeared. He stopped answering my calls. I assumed he was grieving.” Carrick paused, and her voice dropped. “But there was something else. About a year before the fire, Saul was fired from Vectis. Gross misconduct. He'd been accessing systems he wasn't authorised to access. Downloading schematics. Building something in secret.”

“What was he building?”

“I don't know. Aaron never told me the details. But he said Saul was preparing for something. He said Saul believed the only way to fight a system was to become a system.”

Lott stood. “I need to see any photographs you have of Drummond. Any correspondence. Anything at all that might help me find him.”

Carrick nodded and disappeared into the kitchen. She returned with a shoebox filled with papers and photographs. Lott sifted through them. Saul Drummond was a thin, intense-looking man with prematurely white hair and the hollow-cheeked stare of someone who had stopped sleeping a long time ago. In one photograph, he was standing beside Aaron Hyatt at a Vectis facility, both of them wearing hard hats and the easy grins of men who trusted each other completely.

In another, taken after the accident, Drummond was pushing Hyatt's wheelchair along a hospital corridor. The grin was gone. The eyes were different. Something had been ignited in them.

Lott pocketed the photographs. “If Drummond contacts you, don't talk to him. Call me immediately.”

Carrick walked her to the door. As Lott stepped outside, the woman said, “Detective. If Aaron really is alive, what are you going to do?”

Lott turned. “I'm going to stop him.”

“And if you can't?”

The question hung in the damp air. Lott had no answer that wasn't a lie.

She drove back to the constabulary through streets that were beginning to flood. The drainage system was failing, overwhelmed by eleven days of continuous rain. Water was pooling in the underpasses, creeping up the kerbs, lapping at the doorsteps of basement flats. The city's infrastructure was groaning under a load it had not been designed to bear, and Lott could not shake the feeling that this was not a coincidence.

At Clyde Street, she found Cyril Abasi waiting in her office with a laptop and the expression of a man who had seen something he could not unsee.

“I found Saul Drummond,” he said. “Or rather, I found his digital footprint.”

He turned the laptop toward her. On the screen was a personnel file from Vectis Water and Power. Saul Drummond had been a senior network architect, responsible for designing the communication protocols that linked the city's substations, pumping stations, and control centers. His employee photograph showed the same thin, white-haired man from Carrick's shoebox, but younger, less hollowed out.

“He was fired six years ago for unauthorised access,” Abasi said. “But here's the thing—after he left, someone continued to use his access credentials. For four years. The account was never properly deactivated. It was used to access the SCADA network, download schematics, even modify certain control parameters.”

“Hyatt was using Drummond's credentials.”

“Or Drummond was using them himself.” Abasi opened another file. “Because Saul Drummond isn't dead. He's alive and he's active on MirroredCatacomb. He uses the username EchoNull. And he's been coordinating with NullHyatt for months. They're not one person. They're a team.”

Lott stared at the screen. Two ghosts. Two dead men, or one dead man and one who had made himself a ghost. Hyatt with the motive, Drummond with the expertise, and between them the entire city rendered helpless.

“There's more,” Abasi said, and his voice dropped. “I traced some of the forum traffic. The server isn't offshore. It's here, in Port Fergus. It's running out of a disused pumping station on the estuary. The same pumping station that Aaron Hyatt helped design in 2014.”

Lott grabbed her coat. “Get me the address. And get Malone. We're going in.”

The pumping station was a Brutalist concrete box marooned on a spit of mudflats at the mouth of the River Clyde. It had been decommissioned in 2019 after a flood damaged the turbines, and it had sat empty ever since, a favourite haunt of urban explorers and scrap thieves. When Lott's car pulled up, the building was dark and silent, its windows blanked with rusted metal shutters.

Malone and a tactical team were already there. The rain had returned with a vengeance, hammering the mudflats with a sound like gravel on a tin roof. Lott pulled on a tactical vest and checked her torch.

“No lights,” she said. “No radio signals. If Drummond's inside, he'll have every sensor in the building rigged. We go in quiet and we go in fast.”

They breached the door at the back of the station, a rusted steel panel that gave way with a shriek of corroded hinges. Inside, the air was cold and wet and smelled of diesel and salt. The main turbine hall was a cathedral of rusted machinery, its floor slick with standing water. Pigeons exploded from the rafters, their wings beating a frantic percussion against the concrete.

Lott moved forward, her torch beam cutting through the darkness. At the far end of the hall, a metal staircase spiralled down into a lower level. She could hear something below—a hum, faint but constant, like a refrigerator heard through several walls.

They descended. The lower level was a control room, its walls lined with panels of switches and dials that had not been used in years. But in the center of the room, incongruously new, was a rack of servers. They were running, their lights blinking in orderly green and amber sequences. Cables snaked from them across the floor, connecting to a makeshift console built from salvaged monitors and keyboards.

The console was active. On the largest screen, a command prompt blinked: Null Protocol Active. Awaiting input.

Lott stepped closer. There was a note taped to the monitor, written in sharp, angular handwriting.

Detective Lott,

Welcome to Station Zero. I hope you appreciate the symmetry—the system that was designed to pump water out of this city is now being used to pump justice into it. You're too late to stop what's already in motion, but I admire your persistence. Persistence is the only thing the FSA never took from me.

I am not your enemy. The system is your enemy. I'm just the null pointer that tells the system it's wrong.

—NullHyatt

P.S. Check the water pressure at the FSA headquarters. You'll find it... instructive.

Lott grabbed her radio. “Get a bomb disposal team to the FSA building. Now. And evacuate everyone within a two-block radius.”

She turned and ran back up the spiral staircase, her boots splashing through the rising water on the floor. Behind her, the servers hummed on, indifferent, continuing to execute protocols that had been set in motion long before anyone knew they existed.

Outside, the rain had become a deluge. The river was rising. And somewhere in the city, another system was about to fail.