Read Chapter 31: The Second Lock

The flotilla had moored along the old Embankment, where the water now sat level with the third-floor windows of the abandoned offices. Finn wiped sweat from his forehead—the fever still clinging to him like a second skin—and studied the laminated chart spread across the deck of the *Margaret Rose*.

Dr. Chen traced a finger along the outer sea wall. "It's here," she said. "The secondary lock. No one's touched it in forty years."

Mara leaned over her shoulder. "Secondary to what?"

"To the main barrier gates—which we just opened." Chen's voice was tight. "The engineers who designed the system knew the main gates couldn't hold forever. They built a second line of defense farther out, where the Thames meets the sea. A final lock that keeps the entire tide out, not just the surge."

Carver grunted. "So we fixed one problem by breaking a bigger one."

"Not exactly." Chen straightened. "The secondary lock was always meant to be the backup. But its valves were never designed for sustained pressure. The data I've been pulling from the maintenance buoys shows it's been straining for weeks. The equalization put enormous stress on the system."

Finn caught her hesitation. "How bad?"

Chen met his eyes. "If it fails, the whole city floods. Not zone by zone. All of it. The water won't rise gradually this time. It'll come through the lock like a wall and there won't be anywhere high enough to go."

For a moment nobody spoke. The lapping of water against the hull seemed louder.

Tess pulled her damp hair back from her face. "You said there was a fix."

"There is." Chen spread her hands over the chart. "The lock has a control valve deep in the old maintenance tunnel. It needs to be replaced—manually. The tunnel runs beneath the estuary floor. It's flooded, pressurized, and the valve housing is seized from corrosion."

"How deep?" Anya asked.

"Eighty feet. Maybe more. The tunnel was built in the 2030s, before the first raised walls. It wasn't designed for human access after the system went live."

Finn studied the chart. The tunnel snaked out from the shore, thin and vulnerable. "If we could get the valve replaced, the lock holds?"

"For another generation, at least. The housing is intact. It just needs a new core." Chen pulled a sealed cylinder from her bag—about the length of her forearm. "I've been working on this for three years, ever since I realized the secondary lock was degrading. I never had the opportunity to install it. Or anyone willing to try."

Danny shifted on a crate near the cabin door, still favoring his bandaged side. "Can't we send a drone? A submersible?"

"They'd have to navigate a flooded tunnel with zero visibility, bypass two crush-gates, and work a seized valve loose with minimal clearance." Chen shook her head. "A drone doesn't have hands. It doesn't have judgment. The valve needs someone who can feel the obstruction and work around it."

"Then we train someone." Finn's voice was hoarse. He coughed, and Mara shot him a look.

"Training takes weeks," Chen said. "The lock is rated for days. We don't have weeks."

"So what you're telling us," Carver said slowly, "is that the whole city's about to drown, and the only way to stop it is to send someone down into a flooded tunnel to do a repair that's never been done in conditions like this, with no guarantee they'll come back up."

Chen nodded. "That's exactly what I'm telling you."

The silence stretched. Finn traced the tunnel route again. He knew what he should say. He was the former marine engineer. He knew valves and pressure systems better than anyone on the flotilla. But his hands were shaking harder than they had an hour ago, and the fever had drained the strength from his legs.

"I'll do it."

Every head turned to Anya.

She stood at the railing, water dripping from her fingertips. Her face was calm, almost peaceful. "I said I'd go to the core for the gate key. I wasn't afraid then. I'm not afraid now."

"Anya—" Finn started.

"Don't." She held up a hand. "You're sick. You've been running on willpower for a month. Your hands tremble when you lift your coffee cup. If you go down there, you'll die before you reach the valve."

Finn's jaw tightened. "You don't have dive training."

"I grew up swimming in these streets." She gestured at the flooded city around them. "I've been underwater longer than you've been on boats. And I read faster than anyone else—I know the schematics from the chart already."

Chen looked at Anya with something like appraisal. "Do you understand what you're volunteering for?"

"Yes." Anya's voice was steady. "I'm volunteering to save every person in this city, regardless of what zone they live in. That's the whole point now, isn't it?"

Mara stepped forward. "I'll go with her. Two divers are better than one."

"No." Anya shook her head. "The tunnel's too narrow. One person needs to move freely. Two will just get in each other's way if something goes wrong."

"Then you have a radio," Carver said. "You stay in contact. Any sign of trouble, you surface."

Chen frowned. "There's another complication. The tunnel mouth is shielded by a debris screen that's been accumulating silt for decades. We need to clear access before anyone can reach the valve housing."

"We have nets," Finn said. "Cables. Boats. We can clear the mouth."

"Not entirely." Chen pulled a second chart from her bag—a schematic of the outer wall's base. "The screen is designed to be opened externally only from a service shaft located inside the lock chamber itself. But the chamber is already partially flooded. It's accessible, but barely."

Finn studied the schematic. "There's a hatch."

"Yes. About three feet of clearance to get through, then a vertical drop into the chamber. From there, you'd work your way through the wall to release the screen."

As she spoke, Finn noticed Anya watching him. Her expression was odd—half determination, half something else. Before he could speak, she moved closer.

"When I go down," she said quietly, "there's something I need to give you."

She reached into her jacket and pulled out a small waterproof pouch—exactly the kind Danny carried his evidence in. She pressed it into Finn's hand.

"If I don't come back, this goes to Tess. She knows what to do with it."

Finn's throat tightened. "Anya—"

"I've been carrying that since the day the walls went up." She gave him a small, sad smile. "It's the reason I told you I wasn't afraid. I've already faced the worst thing that could happen to me, and I'm still here."

The tears he didn't let fall threatened to surface. He pressed the pouch back toward her. "Then you'll be the one to deliver it. When you come back."

Anya shook her head. "I don't want a burden that heavy while I'm down there. Hold it for me. That way I've got a reason to fight for the way back."

She stepped back before he could argue. "Dr. Chen. When do we start?"

Chen glanced at the darkening sky. "The tide turns in six hours. We need to be at the lock before it does."

"Then we move now." Finn pocketed the pouch despite the weight of it. He turned to the flotilla. "Carver, take two boats and recon the lock approach. Mara, you're on comms—get every radio we have working. Danny, you're with Dr. Chen on the technical side. Tess—"

"I know." She was already pulling out her recorder. "I'll document everything. If the lock fails, the world will know exactly what happened here."

Finn nodded. He looked back at Anya. Her eyes were calm, but her hands had begun to tremble—just slightly, barely visible.

She wasn't as unafraid as she pretended.

He crossed the deck and took her hands in his. "Come back," he said.

"I will."

"You don't know that."

She squeezed his fingers. "I know that I'm not leaving you to carry this alone, Finn. Not after everything you've carried already."

He didn't have words for the gratitude that swelled in his chest. So he just nodded, watching as she turned to follow Chen down the ladder to the launch boat.

The tide was rising. Six hours until it would turn—six hours to reach a failing lock, clear an impassable debris screen, and send a woman down into dark water to save a city that still couldn't decide if it wanted to be saved.

Finn touched the waterproof pouch in his pocket. Whatever Anya had been carrying since the walls went up, he knew it wasn't just evidence. It was proof that this fight had always been bigger than the gates—bigger than the zones—bigger than any one flood.

The lock was failing.

But Anya was going to dive anyway.

And Finn had never felt more helpless in his life.