Andrew was sitting in the living room, feeling guilty and ashamed, when Cheval descended the stairs again with a piece of paper in his hand. "Look at this," he said, thrusting it in his face.

     Andrew took it from him and read it. It was still warm from the printer. His eyes widened with alarm. "They can't do this!" he said, rising from his seat.

     "They've done it," said Cheval with savage satisfaction. "You are deputised, mate. You are now an acting member of the New London constabulary and you are required to follow any lawful order I give you or you'll be thrown into a cell the moment we get back to the city and you'll be looking at your lovely wife and your wonderful children through iron bars for the next six to twelve months. On top of that, your rover will be confiscated and you'll be found useful employment as a common labourer for the rest of your working life."

     "Ordering me to risk my life isn't a lawful order."

     "Keep reading," Cheval told him. "The Commissioner himself is giving us our orders, and he's ordering us, you and me, to take out the sentry weapon by any means necessary so we can continue our pursuit of Reginald Fox. So buckle up, buttercup. We're going for a walk."

     "It doesn't take both of us," Andrew protested. "If all you're going to do is flip a switch and turn it off..."

     "It does take two of us," the Sergeant replied, however, fixing him with his eyes. "They included a set of schematics for the weapon, so go get suited up."

     "I don't know how to climb a mountain!" protested Andrew, playing his last card. "I don't think anyone's climbed a mountain since The Emergence."

     "I looked at a terrain map," said Cheval. "Doesn't look too steep."

     He led the way into the cockpit and Andrew followed with strangely mixed feelings. Still afraid, but strangely relieved as well, as if he'd always wanted to go with Cheval and had just needed an extra push to overcome his very natural reservations. He plopped into the seat beside the Sergeant as he took the pilot's seat and pulled the map onto a monitor screen. "There," he said, pointing. "Just like climbing a flight of stairs. So long as we only touch the ground with out hands and feet we'll be okay." He stared more closely at the map. "I think I can see a route that'll allow us to get within fifty metres of it before it knows we're there..."

☆☆☆

     The sides of the valley had a one in one slope at the point where they had to climb it. Andrew and Cheval had to climb upwards on their hands and feet, ready to keep hold with their fingers if their boots suddenly slipped on the ice. Even though their gauntlets were padded and insulated, Andrew could still feel the cold trying to seep in. Whenever they came to a more or level place where they could stand they would stop for a moment with their hands away from the icy surface while they waited for the heating elements in the palms of their gauntlets to warm them again.

     They couldn't wait too long, though. Not only was Fox getting further ahead with each passing minute but their surface suits only contained enough battery power for six hours. When that power was used up they would start getting cold fast. As soon as the numbness in their hands gave way to the prickly pain that told them they were coming back to life again, therefore, they put their gauntlets back to the ice and began climbing again, kicking the toes of their boots into the granite-hard water ice so that the forward pointing cleats could find the tiny cracks that had opened in it as the ice had continued to cool and shrink.

     "You're drifting too far to the east," said Windsor's voice in their ears. "You need to keep to the west to stay out of sight of the sentry weapon."

     "The slope's too steep to the west," Cheval replied. "I've made accidental contact with the ice with my knees several times already. I don't want to get frostbite."

     "You don't want to get your head vaporised by a fifty kilowatt laser beam either. Keep to the west."

     "We'll try." Cheval looked around, assessing the irregular terrain as best he could. The sun had dropped below the western mountains some time ago leaving them in almost total darkness and he was relying on his helmet light to see by. "I think there's a way up over beside that rock," he said to Andrew.

     Andrew looked. As he raised his head, though, his helmet light spilled across the bare rocks further up, rocks that had to have been in sight of the sentry weapon. He quickly ducked back down again. "How does it spot targets?" he asked. "Will it target a moving spot of light?"

     "Target?" Cheval replied. "No, but it will attract its attention to the area. It has low resolution microwave motion sensors and visible light cameras looking in all directions all the time, but if something attracts its attention it'll direct its high resolution camera towards it. The thing is supposed to be quite smart. At least corvid level intelligence."

     Andrew nodded anxiously. "And how long will its attention stay in that area, assuming it doesn't spot anything?"

     "Depends on what it learned when it was last active. If nobody came this way during The Freeze it'll only have the knowledge and experience that was programmed into it in the factory, but if it saw any action, if people tried to get past it during The Freeze, it will have gained new experiences."

     "You think any of them will have tried what we're trying?"

     "There were six sentry weapons stationed here back then, along with a whole battery of cannons and machine guns. The gap in its defences didn't exist back then."

     "You said it's smart. Is it smart enough to know that it's vulnerable from above and adapt its behaviour accordingly?"

     "Your guess is as good as mine."

     Well, that's reassuring, thought Andrew as he edged his way along to the rock Cheval had spotted. Reaching it, though, he was relieved to see that the way was easier from there on. The slope was less steep and there were knobs of bare rock protruding through the ice that his boots could get a good grip on. The cleats would be getting blunted, though. He would have some maintenance work to do when he got back to the rover.

     An hour went by as they continued to climb, and then another hour in which they made their way eastwards along a more or less level ledge that might once have been a footpath. There was a mummified body lying on the path, dressed in thick furs, the flesh so perfectly preserved and so perfectly white that it looked like a marble sculpture except for the burns around the eyes. Andrew looked around for the weapon that had killed him and saw it about a hundred metres away to the west, barely visible in the starlight. It was dark and dead. A piece of modern art left behind by a lost and forgotten civilisation. He watched it just in case, remembering Cheval's warnings that some of the ancient weapons might still be operational even in the absence of Fox's attention, but the stubby barrel of the laser was pointing the other way and didn't move. Breathing a sigh of relief he continued on his way.

     "This is taking too long," he said as they reached the highest point and began to descend the other side. "We won't get back to the rover in time. We'll run out of power."

     "The weapon may have an external power point," Cheval replied. "We'll be able to recharge our suits."

     "May?" said Andrew in alarm. "It may have?"

     Cheval sighed. "Windsor, look at the weapon schematics," he said. "See if it had an external power point."

     "I don't see one," the Constable replied a few moments later.

     "Well, that's probably because it's only describing its operational capabilities. What it can hit, How hard it can hit it. There'll be a power point. I'm confident of it."

     "And if there isn't?"

     "If we get a move on it won't matter. We can get there and back with the power we've got."

     I'll give it another hour, thought Andrew. If we haven't gotten there and turned it off in that time, I'm heading back. I'm not freezing out here for him. Not for a few bars of metal. He can rant and rave all he wants, I don't care. One hour. One hour more.

     He picked up the pace, though, taking the downward path a little faster than was safe as a sense of urgency began to grow inside him. Only when he slipped and fell onto his bottom did he realise the risk he was taking and slow down. It had only been a momentary contact but it had been enough to leave his backside numb with cold. Idiot! he scolded himself. Be careful! Three seconds of contact, anywhere other than the hands or feet, is enough to cause frostbite. A serious, crippling injury. Remember where you are.

     "Twenty metres further," said Windsor over the radio link. "You're almost there."

     "Get the bug ready," Cheval replied.

     "Already is," the Constable said. "Just waiting for you."

     A few minutes later they'd reached the spot they'd been aiming for. The closest they could get to the sentry weapon without it seeing them. Cheval reached into the pouch on his belt and took out a small pocket mirror that had belonged to Jasmine. He'd found it in the childrens' bedroom. He raised it up above the rock they were sheltering behind and used it to look at the sentry weapon, Andrew crowded close behind so he could see it as well.

     One glance was enough to tell them that it was fully functional. A pair of tiny yellow lights glowed near its base, near the spot where its control electronics were located, and a pair of small cameras beside the main laser drum were turning this way and that as it searched the valley for targets. More than that, though, it looked alive. It radiated a sense of menace, a sense of evil, as if it were some fearsome predator. Asleep for now but ready to awaken at the slightest disturbance. It made him want to slink away back the way they'd come, back to the safety and comfort of the rover, but if he did that he knew that the memory of his cowardice would haunt him for the rest of his life. He took a deep breath to steady himself and gather his courage.

     If Cheval was feeling the same thing he gave no outward sign of it. "Get ready to run," he said to Andrew. "When the bug distracts it we'll have just a few seconds to get into the cover of its blind spot. If you're slow, you're toast. Got it?"

     "Got it," Andrew replied.

     Cheval studied Andrew carefully, trying to see his face through the visor of his helmet. Andrew knew he was trying to see whether he really would run. Would fear freeze him to the spot? If that happened, Cheval couldn't deactivate the weapon on his own, and with the bug destroyed they wouldn't have another distraction to allow him to retreat from the weapon. If Andrew didn't run with Cheval, then Cheval would die. "I'll run," he assured the Sergeant. "I will."

     Cheval studied Andrew for a few moments longer, then nodded.,"Okay," he said. "Windsor, send the bug in, and tell us immediately the weapon reacts."

     "Got it," Windsor replied. "Sending the bug in now."

     Andrew and Cheval tensed up, ready to run the moment they got the word. The mountain was bare rock here, but uneven enough that they hoped their boots would still get a grip on it. If they slipped or tripped, though, that would be bad. They would have three or four seconds before the sentry could spin around to bring its weapon to bear upon them. If they hadn't reached the blind spot by then, they were dead.

     Seconds went by, though, and nothing happened. "Windsor?" said Cheval. "What's happening?"

     "The bug's just fifty metres from the sentry now," said the Constable. "In plain sight of the weapon. Ah, the high definition camera's turning to look at it... Oh no."

     "What?" demanded Cheval impatiently.

     "The high definition camera's now looking in your direction. It's sweeping back and forth across the ridge you're hiding behind. It must know you're there."

     "Corvid level intelligence," said Andrew, his eyes wide with alarm. "It knows the bug's a distraction."

     "Then we have to make it a threat it can't ignore," said Cheval. "Windsor, take it closer. Deploy the manipulator arm. Use it to pick up a rock."

     "Right." There was a pause. "Forty metres from the sentry now. Still no reaction."

     "The bug can't do anything to a sentry," said Andrew in confusion.

     "What if it's carrying a bomb?" asked Cheval.

     "It's not. You used up all the explosives in Augsburg."

     "The weapon doesn't know that. It's smart, but not that smart, I hope. I'm hoping it's programmed to treat anything unfamiliar as a threat. It can see the bug's carrying something..."

     "A rock," said Andrew. "It's not going to be scared of a rock."

     "Something that looks like a rock," replied Cheval. "Hopefully it's not smart enough to positively identify it as a rock."

     "It's reacting," said Windsor, his voice tense and excited. "It's turning its high resolution camera back towards the bug. Thirty metres away now... Go! Run!"

     Cheval and Andrew leapt from their hiding places and ran. Andrew had his attention on the ground at his feet, looking for smooth patches and trip hazards, but he saw a bloom of light out of the corner of his eye. The bug being destroyed by a full powered blast from the laser beam. Then the weapon began to spin with terrifying speed, back towards their direction. Andrew ran faster, sobbing with fear. Over the intercom he heard Cheval panting with effort as he also ran beside him. For a moment Andrew considered slowing, to allow the Sergeant to pull ahead of him. Presumably, the weapon would kill the man in front first, giving Andrew a chance to get to safety. Surely the weapon wouldn't kill someone who was retreating, would it? He cursed his cowardice and put the idea out of his head, continuing to run with all his might.

     His boot slipped on the rock and he staggered, steadying himself with a hand on another rock. He pushed himself on and ran again. There was a blinding flash of light, and then he crashed headfirst into a solid metal wall. He began falling to the side and Cheval grabbed his arm to pull him back. "Relax," he said. "We made it. We made it."

     Andrew blinked repeatedly, trying to summon tears into his eyes. The flash had left a vivid after image across his entire visual field. Inside, though, he was feeling strangely light headed, almost as if he were drunk. "We made it," he said, glowing with pride and relief. He'd done it. He'd run with Cheval. And the Sergeant had trusted him enough to run, knowing he was dead if Andrew hadn't come with him. God, but it was a good feeling! No wonder the bond between soldiers was so strong. No wonder they would follow their commanders to almost certain death. Andrew had never taken recreational drugs, but he was prepared to believe that they made you feel the way he was feeling now.

     Then he remembered the flash. "Did it get you?" he asked.

     "No. We made it."

     "But it fired! I saw it!"

     "I think it fired in desperation. Knowing it wouldn't hit us but firing anyway, just on the off chance."

     "You make it sound almost alive."

     "Yes, well, it's human nature to anthropomorphise things."

     The barrel of the laser weapon was turning this way and that above them, its angle depressed as far as it would go. To their left they saw another sentry weapon, dead and motionless, like the one they'd seen on the way up. If it were still functional, if Fox had been able to restore two of the machines, the other would have fired on them by now, each weapon's blind spot covered by a neighbour, but the sentry was alone now. A situation it had never been designed to find itself in.

     Then he saw the reason for their good luck. As his vision began to clear, he saw the atomic power sources from three other sentries lying on the ground, connected to the working sentry by thick cables. The plutonium had decayed to the point where it took the power sources from several sentries to bring just one back to full power.

     "Let's put it out of its misery," he said. "Before it thinks of some other way to get us."

     "Right." The maintenance hatch at the base of the sentry was made of thick steel, held closed by two sturdy locks, but it had taken the rover's 3D printer just a couple of minutes to print a couple of keys using templates sent from New London. "Here's where we find out if the information they gave us is accurate," he said as he handed Andrew one of the keys. "If the New Romans changed the locks..."

     Andrew nodded apprehensively. The sentry had no external power point that he could see, and his surface suit only had three and a half hours of power left. If the keys didn't fit they wouldn't be able to shut down the weapon. Even disconnecting the other power cores wouldn't help since the sentry's capacitors were fully charged. Enough power for several shots at full power. They would have the choice of either making a run for it and being shot in the back or waiting until their suits ran out of power and they froze. He felt a sudden strong camaraderie with Cheval, that they were sharing this danger together. He wondered whether Cheval was feeling the same thing. Probably not, he thought. This is probably just another day at the office for him.

     He saw Cheval growing tense as he inserted his key into the hole at the top of the hatch. Andrew inserted his own key. "On three," said Cheval, looking at him through the faceplate of his helmet. "Ready?" Andrew nodded. "Okay," said Cheval. "One, two..."

     They turned their keys at the same time and sagged with relief as the hatch popped open. Beneath was a control panel with a keyboard and a monitor screen. With the control codes having been changed by Fox, Cheval couldn't use the keyboard to shut down the sentry so he just took the pistol from the holster on his belt and fired several bullets into it. The bullets tore through the keypad into the motherboard beneath and the machine died, the status lights on its side going dark and the barrel of the weapon itself coming to a halt above them.

     Cheval stood, the set of his body showing relief and satisfaction. "Well, that's that," he said. "Let's get out of here."

     Andrew nodded, feeling a giddy sense of joy and pride, and the two men began making their careful way back down the slope of the mountain.