"Greetings, fellow police officers," said Andrew cheerfully.

     Cheval and Windsor were sitting in the cockpit, staring out the window at the tracks left by Fox's rover stretching out of sight ahead of them. The ground was almost perfectly flat except where the ice had been either pulled apart to create fissures and crevices or pushed together to create pressure ridges decades earlier. As the last of the ice's residual heat had ebbed away the processes that had created these features had ceased, but the uneven terrain meant that the rover vibrated and shuddered as it drove across it.

     If one ignored these small features, though, and fixed one's eyes on the horizon, the land was perfectly flat. When Andrew had gone upstairs to get a few hours sleep they'd still been in the Alps, but now they were driving across Mediterrania Planitia, what had once been the Mediterranean sea, towards what had once been the island of Sicily. It was a straight race now between them and Fox, and they were growing closer with every kilometre they covered.

     "You're only an acting police officer," Cheval reminded him without looking around. "Just until we get back to the city. Then you'll be officially discharged and free to go back to what you call your normal life."

     "But with a couple of good stories to tell," said Windsor, who did look around. "And probably an award for bravery to hang on your living room wall. I envy you, Andy. What I wouldn't have given to have gone in your place."

     "How's your leg now?"

     "Better. Just need to rest it for a few days, I think, and it'll be as good as new."

     "Good." Andrew leaned forward to see the monitor screens. "So, how far behind him are we now?"

     "No way to tell for sure," Windsor said, "but for a long time we weren't gaining on him. Across the Planitia, where he could be confident there were no hidden hazards, he was free to drive at full speed, as we were. It's only now that he's in the highlands again that he's been forced to slow down."

     "So we're almost across the med?" said Andrew.

     "Just coming up to the Highlands now," the Constable said. "Look."

     He pointed forward through the cockpit window and Andrew saw mountains on the horizon, shining in the light of the distant sun. "So it's almost over," he said. "One way or another."

     "Just a few dozen kilometres now from Etna Mons," said Cheval, his eyes still fixed on the monitor screens. "He might be just over the horizon or he might have reached the volcano already. No way to know, so we're going just as fast as we can, just in case..."

     There was a loud bang and a radiating pattern of cracks spread across the window. All three men jumped in alarm, staring at each other as if one of the others would be able to tell them what had just happened. "Something just hit us," said Windsor in confusion. "How is that possible?"

     There was another bang and another pattern of cracks appeared on the other side of the window. "Someone's shooting at us!" roared Cheval. He pulled on the joystick and the rover spun around, sideways on to the sniper hidden somewhere on the ice ahead of them. Andrew felt his stomach clenching up with fear. If their attacker had some kind of heavier weapon they were a sitting duck. Even a small missile would rip a man-sized hole in both layers of the rover's hull, and the door to the cockpit was the only one that was airtight. They would he trapped in the cockpit, helpless to do anything but wait while their attacker moved to a position where he'd have another shot at the window.

     There was no explosion, though. "He's just got a rifle," said Cheval thoughtfully. "The only damage he can do to us with a rifle is to the window. If we reverse towards him, then spin around when we reach his position, we can show him a clean pair of heels as we carry on our way."

     "He'll have chosen this spot for a reason," said Andrew, though. "There'll be some kind of hazard ahead of us. A crevasse or something, and all our lights and cameras are pointing forward. We'd be reversing blind into a trap."

     Cheval cursed as he realised he was right. "Okay, we'll have to go out and get him," he said.

     "There's no cover, and he's got a rifle," Windsor pointed out. "He'll pick us off like ducks at the fairground."

     Cheval turned to Andrew. "When we were fixing the rover's broken leg I saw some sheets of steel in the spare parts cabinet," he said. "How long would it take to rig up some kind of shield? The ammo he's using failed to penetrate the window, so it must be a small gun, which makes sense. It had to be small enough for him to hide it at the dig site. Five millimetres of steel will probably be thick enough."

     "The only steel plate I've got is twelve millimetres," said Andrew, though. "It'll be heavy. A sheet large enough for you to shelter behind will be getting on for fifty kilos."

     "Get down there are get to work. Just cut out an oval shape and weld a couple of handholds onto it. And fast! The rover's getting closer to the volcano every second." Andrew nodded and dashed from the room.

     While they waited, the two policemen stared out the window. "Why can't we see him?" said the Sergeant. "He should be visible in infra-red."

     "He could be lying down behind a ridge," said Windsor. "Or standing in a shallow crevice. He'd need some kind of insulating blanket to protect himself from the cold."

     "Which means he can't move around," said Cheval, nodding. "Not without giving away his position. First break we've had. We're going to have to let him take a pot shot at us. The camera will see the heat of the muzzle blast."

     "And hope we've got our shields pointing in the right direction."

     Cheval shrugged. "Well, if you wanted an easy life you could have gotten a job in the algae farms. Is your foot up to a little stroll?"

     "I assume we'll be shuffling along under the weight of these shields. We won't be running any marathons. I'll be okay."

     Cheval nodded, and the two men stared at the image on the monitor screen taken by the infra-red camera, hoping that Fox would slip and let himself be seen. "Every minute he keeps us pinned down here is a victory for him," the Sergeant muttered unhappily. "Let's hope Mister Birch doesn't spend too long looking for perfection. If he really is a remainer, this would be the perfect moment for him to drag his heels. Get back there and make sure he's getting his skates on, will you?"

     Windsor nodded and rose from his seat, following Andrew to the rear of the rover.

     Under the Constable's watchful eye, Andrew had a pair of rather crude shields finished in fifteen minutes. "Try not to let them come into contact with the ice," he advised as Windsor took one and tested its weight. "I'm not sure if the weld will hold if it cools too rapidly. Ideally, I'd like to leave it for a couple of hours to cool down."

     "Not an option, I'm afraid," Windsor replied, looking at the new welds where the handholds met the flat, oval sheet of steel. He went to the intercom on the wall and pressed the button to activate it. "Sarge? The shields are ready."

     "On my way," came Cheval's voice from the intercom. "Send Birch up to the cockpit to watch the camera feeds. I need to know the moment Fox reveals himself."

☆☆☆

     The monitor screen showed Windsor and Cheval as two points of bright yellow as they moved away from the rover, spreading out so as to approach Fox's most likely location from two directions. "You guys okay?" asked Andrew.

     "It was a bitch getting the suit on over my swollen ankle," said Windsor's voice over the intercom. "Now it's on, though, the compression seems to be helping. My ankle's feeling a lot better."

     "Focus please," said Cheval, sounding tense and impatient. "We're not out here for our medical benefit. Windsor, keep your shield raised."

     Andrew saw the yellow blob on the right shift slightly and imagined the Constable crouched down, keeping his head lower than the top of the sheet of steel he was hiding behind. The temptation to lift his head to look over the top must be almost overpowering! He was surprised to find himself wishing he were out there with them. He'd had a taste of the camaraderie of sharing danger with someone and he liked it. Those two men out there were sharing it now and he envied them. He felt that he was being left out of something warm and precious, as if they'd been invited to a party and he'd been left at home alone. Don't be an idiot, he told himself. There's a madman out there willing to kill all of us to get what he wants. I should be grateful to be in here where it's 'relatively' safe.

     The Sergeant's channel fell silent. Andrew imagined that he was broadcasting on a different channel, trying to reach Fox. Trying to persuade him to give himself up. It must have failed because his channel came to life again after a few moments, although Andrew could hear nothing but his steady, laboured breathing.

     The two yellow blobs crept on. They were about two hundred metres from the rover now and an equal distance from each other. Andrew wondered whether they still had their shields facing forwards, to the south. If they were, and they had misjudged how far out Fox was, he might now have a clear shot at their sides. At any moment he might hear a cry as one of them was hit, the bullet tearing through insulated, triple weave fabric and then through fragile flesh and bone...

     "Something hit my shield!" cried Windsor. "A bullet! Low down. He was aiming for my legs."

     "Where?" demanded Cheval.

     Andrew hit the monitor's rewind icon to replay the last few seconds. The computer highlighted the spot for him. A green circle around a tiny spot of bright white. It only lasted for a moment, but a dull red glow remained. The muzzle heat of Fox's rifle. "Got him!" he cried. "About three hundred metres ahead of you. At your one o'clock, Cheval. At your eleven o-clock, Windsor."

     Knowing the shot would have given him away, Fox rose from his hiding place and ran. Andrew saw the tiny spot of red turn into a much larger spot of yellow that moved rapidly. "Windsor!" cried Andrew. "He's heading for you. Fast."

     "I see him," the Constable replied. "Can't shoot with this bloody shield..."

     "Don't drop it!" the Sergeant ordered him. "That's what he wants, to trick you into lowering your shield. I see him too." His channel fell silent again and Andrew knew he was talking to Fox again, telling him to surrender. Andrew saw Fox's yellow blob pause in mid step and flare white as he fired again. Cheval's yellow blob jerked. "Cheval!' he shouted. "Cheval!"

     "What's happening?" cried Windsor.

     "I think Cheval's hit..."

     "I'm hit!" said Cheval as his channel came alive again. "Stupid! I did exactly what I told you not to do. Take him out, Windsor. Just take him out."

     "Roger that. I can't see him. Where is he, Birch?"

     "About fifty metres from you, to the south. He's moving towards you again."

     "Still can't see him. Dammit! Which way's south? I got turned around... A bullet just hit my shield. And another."

     "He's now south west of you. I think he's trying to get around your shield. Turn it a little to the right or you'll be exposed."

     "I see him! Dammit, that one bounced right off the top of my shield. Must have just missed my head. This has gone on long enough..." Windsor's yellow blob flared white. "Dammit, missed! He's covered his suit in something white, for camouflage. I keep losing him."

     Andrew held his breath anxiously. Windsor and Cheval's suits were bright orange, to make them easier to see. That was working against them now, and with Cheval hit it was one against one.

     "He's thirty metres away now," he said. "He's running fast, straight towards you. Twenty five, twenty metres..."

     "I see him!" Andrew saw the image on the screen flare again as the Constable fired his weapon. Then Fox was shooting back, forcing Windsor to crouch down behind his shield. A moment later the two hot spots on the monitor screen merged and Andrew imagined Fox barrelling into the shield, knocking the Constable backwards onto the ice. Sounds of a struggle came over the intercom. "Don't let him press you down onto the ice!" shouted Andrew. "Get him off you!"

     The sounds of struggling and laboured breathing continued, though. Andrew imagined Fox sitting astride the Constable, one hand on Windsor's wrist keeping him from aiming the gun at him. Windsor's back would be freezing as the ice sucked heat through the thin padding of the surface suit. It would only take a few seconds before he suffered permanent injuries from frostbite. Thirty seconds and he would be dead.

     Then, abruptly, the single heat spot on the monitor screen separated into two again. Windsor must have thrown Fox off and would be scrambling back to his feet as fast as he could. "Shoot him!" shouted Andrew frantically. "Finish him while you can."

     "No need," said the Constable, though, his breathing heavy and laboured. "He's down."

     "You shot him?" said Andrew doubtfully. He hadn't seen the bright flare of a hot muzzle flash.

     "I shot him," said Cheval. The pain he was in was evident in the tone of his voice. "Bastard forgot about me."

     So had he, Andrew realised with chagrin. He'd been so focused on Fox and Windsor that he'd forgotten about the Sergeant. "How bad are you hurt?" he asked. "I'll come out and help you."

     "I'd appreciate that," Cheval replied. "Windsor, how's Fox?"

     "Still alive," the Constable replied. "His suit sealed itself but he has to be bleeding. You hit him high in the chest. He's probably got a collapsed lung. God knows what else if the bullet hit a rib and shattered it."

     "Can you get him back to the rover?"

     "How are you?" Andrew butted in. "Are you hurt?"

     "My back," Windsor replied. "I was on the ice too long. I'm still on my feet, though. I can get him back to the rover."

     "Okay," said Andrew. "Cheval, I'm coming to get you. Hang in there."

     He then dashed from the cockpit, running for the outfitting room, leaving the channel open behind him.