Once the city used to pulse with energy. Dirty and dangerous, but alive and wonderful. Now, it's something else.

The changes came slowly at first. Most didn't realize, or didn't care, and accepted them. They chose a comfortable life. Some didn't. And those who refused to conform were pushed to the sidelines; criminalized.

They became our clients.

We call ourselves Runners. We exist on the edge, between the glass and the reality: the mirror's edge. We keep out of trouble, out of sight, and the cops don't bother us.

Runners see the city in a different way. We see the flow. Rooftops become pathways and conduits, possibilities and routes to escape. The flow is what keeps us running…

…keeps us alive.

Faith opened the roof hatch and stepped out into the afternoon sunlight, squinting in the brightness after the colorless stairwell. Standing up high on the roof, the sounds of downtown traffic at street level were muted by distance. Only an occasional horn or revving engine reached her ears if they were close enough and loud enough. Even higher than her, a commercial airliner traced a single contrail across the blue, featureless sky, its engines even quieter than the ones on the street.

"Well Faith, what do you think of the new training ground? Pretty slick, huh?"

She stepped further out onto the roof, surveying the area around her. It was another construction project. There was one mainly unfinished building with a crane rising out of a jungle gym of I-beams and unfinished levels, with material piled up everywhere. Half the roof was finished, the other half a skeleton of a frame; the building next to it looked almost completely finished. The city block surrounding it contained finished buildings, but it looked like traces of the construction still spread to the closest edges. There was still plenty of work to be done, but as of right now, the scattered material and half finished constructs were perfect.

She lifted a hand to her ear, pressing the transmitter on her ear piece. "Looks good Merc, but would you mind telling me what happened to the old one?"

"Well, as you know, the city's always growing, and they finally got around to finishing the high-rise on East Side after the labor union strike. Our old training ground is now a bunch discount condos and offices."

"They're bound to finish this one too, sooner or later," Faith said. "I wouldn't get too attached to it."

"Which is why we need to make the most out of it while we can," Merc said pointedly. "Drake and some of his guys scoped the place out a few weeks ago. Surveillance won't be installed for another month, once the construction is finished, and the buildings are low priority, so don't expect too much attention from the public or CPF. If anyone sees you, they'll just think you're a vagrant or hoodlum doing some loitering. Not worth their time when they've got bigger issues to worry about."

The sun beat down on the paved roof, reflecting most of its heat into her as she knelt to check the laces of her new crimson Loggos. The sleek Indonesian-brand shoes fit snugly around her feet, light but with a solid tread on the bottom. The big toe was separated from the rest, making it easier to work into nooks and crannies for climbing. When they were cinched tight, it hardly felt like wearing anything.

There wasn't a cloud in the sky. It was the kind of day to be exploring the city, looking for new routes, or hitting the mall and checking out the new Raposa threads after a day's deliveries. The last thing she wanted to be doing was wasting time running the same three or four buildings over and over again.

"Merc, do I really need to be doing this?" she asked, trying to keep the annoyance out of her voice as double knotting the laces. "I ran all the way here without a hitch. Isn't that enough for you?"

"I know you hate it, but you were out for almost two months after that fall. I know your leg feels fine, but I want to make sure you've still got it before I stick you on a route. The way you took here was child's play; this place has got plenty of tricks for you to try out to make sure you're at a hundred percent."

"Oh, I've still got it," she griped, not bothering to send the message back to Merc. If there hadn't been a GPS tracker in her earpiece, she would have just ditched.

A high whistle made her ears perk. Faith looked over the railing and saw a small waving smear of red against the gray and white roof of the finished building next to her. She smiled when she recognized the blond ponytail and waved back.

"Hey, Cel's here," she told Merc, breaking into a light jog. "I'll talk to you later."

"Alright kid, have fun. I'll check back with you in an hour."

The path to the center building was no sweat. All she had to do was hop a small gap between the buildings and vault an unfinished staircase, and the scaffolding took her right to the adjoining roof. Celeste was waiting for her, finishing up a few last-minute stretches.

"Glad to see you back on the tops, Faith," she said with a warm smile after a quick hug.

"Me too, Cel. Merc's glad that I'm finally out of his place," she replied with a lopsided grin. "I think I was starting to drive him crazy by just hanging around all day."

She shrugged. "Not much you can do with a broken leg."

They spent the next few minutes stretching and catching up on some gossip. Faith stretched all her major muscles, especially the ones in her legs, even if the run there had warmed her up enough. Everything felt just a little too stiff for her taste, but six weeks cooped up on a couch would do that to you.

"Well, what do you say we take it slow?" Celeste offered, bouncing on the balls of her feet as she adjusted her black gloves that matched the leather brace on her left arm. It hid most of the digital tat that snaked around her forearm. Her Loggos were black to match the track pants she wore slung low on her hips. A navel piercing peeked out from the sliver of midsection between her red tank top and waistline. "A little follow the leader? It'll give you a chance to get to see this place up close."

Faith shrugged indifferently. "Sure, why not?"

Celeste took off at a gentle jog, and after beckoning, Faith trailed at her heels. The rooftops were close together, providing easy jumps from area to area, and it didn't take long for her to feel the flow of the new training area. The paths were pretty obvious, with planks and ledges where construction workers had half-finished pointing to jumping spots, and lots of wide open areas to get some speed. After all, it was a training ground; a place to warm up or to practice in safety.

Their initial run was simple: they hopped over to one of the adjacent building via the scaffolding, scaling a few low fences and crossing a few short gaps. Before long, the heat forced a light sweat from her; she was a little out of shape, and she knew it before she stretched, even if she didn't want to admit it to Merc. Running the new training ground was probably a good idea.

But even if she felt out of shape, she could still feel the Flow; the way her body moved over and around obstacles with minimal effort. Each step led to the next one, each jump starting the next one. It was a transfer of speed and momentum, something that kept her moving. Stuttering or tripping disrupted it like turbulence on a plane, ruining the otherwise smooth motion that she and every other Runner tried so hard to perfect.

Celeste eventually stepped it up after moving into an alcove. Even though there was a door installed, most of the room it led to wasn't even finished yet, with half of the walls still skeletal. An I-beam was positioned across to a balcony, the drop below them an easy ten stories. Without so much as batting an eye, she hopped several feet out onto the beam and began to move forward, arms outstretched for balance.

Faith was right behind her. Remembering the all-important rule of don't look down, she focused on Cel's ponytail and keeping her legs moving smoothly. Her arms acted as a balance, making tiny controlled movements to reset her body weight while her feet kept moving in swinging steps to avoid tripping on her cargo pants. It helped some that they were tied off at the ankles.

Celeste stepped onto the surface of the next roof. Seconds later, Faith followed, a little relieved. Crossing a balance beam that high up was second nature, only now not so much after her injury. A fall like that killed, and the only way to deal with that danger was to not talk about it.

Life as a Runner wasn't always vacation.

"Good to see your balance is still in tip-top shape," Celeste said, bouncing once again on her feet to keep her body moving. "Ready for something a little more rigorous?"

"Like what?"

She suddenly reached forward and slapped her on the shoulder, then bolted off running. "You're it!" By the time the impact registered, she had already scaled a wall, breaking into a dead on sprint.

"Dammit!" Faith yelled with a laugh, then took off after her.

The wall Cel had climbed was really only a raised portion of the roof. Faith lunged at it, digging her feet into the concrete walls and letting the treads on her Loggos get a grip. She made it up three quick steps, more than enough to get a hand on the edge and hoist herself up in one motion.

Cel was ahead of her, jumping off the raised section of roof and grabbing a pipe jutting out from some ventilation shafts. She swung herself over a cluster of air conditioners to a drainage pipe, then immediately began to scale it. Faith trailed her, launching off the shed and grabbing the pipe in both of her outstretched hands. She could feel her momentum swing her forward with her hands as the pivot. She let go at the end of the swing, allowing it to carry her body forward with the aid of a little pump from her legs.

Still a little rusty, she lost some forward motion on the swing and hit the drainage pipe a little lower than Celeste. It rattled as Cel skipped to another pipe to the left of them, which she quickly abandoned to grab the ledge of a fire escape. Faith dug her feet into the crease of the pipe and started climbing. Her shoes gripped the side of the building and the metal tape that was used to secure the pipe.

The game of tag continued as both women moved along an unseen path on the features of the roof like it was meant to be scaled. Cel grabbed the edge of the top of the building above them and shimmied along it, then wiggled through a hole in the chain link fence that protected its perimeter. Here, Faith managed to close some of the distance, being slightly better at climbing. Cel had some flashy moves, but when they were toe to toe, Faith had the endurance and efficiency, out of shape or not.

She made a grab for Cel's ankle as she got through the fence just ahead of her, but missed, slapping nothing but hot concrete. The broken metal tines of the chain links scratched at her bare arms and picked at her track tank-top, but she scrambled through just in time to see Cel pull off a triangle jump off of a slab of sheet metal. She was just a breath behind her, resuming the Flow and hitting the sheet at an angle, taking a few gravity-defying steps along it, then twisted and jumped off, grabbing the same scaffolding platform Cel had. With a kick of her legs, she got her elbows onto the platform and pulled herself up.

Up another wall, then across a narrow ledge which both of them had to slowly edge across, but as soon as they stepped off onto a wider path, the chase was back on. Celeste made a break for a high-tension wire that anchored the crane to the building, then jumped and wrapped her hands around it, sliding down it like a zip line.

Faith grabbed the wire, first with the fingerless glove on her right hand, then gripped back of her hand with her left and began her slide. She could feel the intense heat of friction from under the leather of her glove in the calluses of her hand. Most Runners, like Cel, wore two gloves for this very reason. Others could pull it off with just one glove, but it took practice.

Cel dropped off the zip line and fell onto a tarp covered pallet, breaking her fall with the use of her legs and arms. It burned all her forward motion, but the same fate awaited Faith as she mimicked the maneuver, almost dropping on top of her had she not already scrabbled off the pad.

The chase resumed, becoming smoother after the sudden halt in movement. Cel darted over a pipe. Faith went under. She leaped a gap, tucking her legs up to avoid catching the top of a barb-wired fence. Faith did the same, but felt a tine pluck the bottom of her thigh, the fence rattling in response as it nicked her.

It was just after vaulting a crate that Celeste screwed up. After she jumped, she grabbed a hanging ladder from another fire escape on the adjoining roof, but slipped on the rungs, giving Faith the last bit of time she needed to catch up. When she hit the lower rungs of the same ladder, she reached up and snatched her by the cuff of the pants. "Gotcha!"

"Ah, damn!" Cel swore. She laughed, then sagged against the ladder, breathing hard.

Faith joined her, and for a while, the two of them clung to the ladder, laughing. Eventually, she let go, and the two of them finished the route at an easy pace. They were near where they had started anyway, and were soon back on top of the finished building next to the crane.

"Well, I don't know why Merc thought you needed practice," Celeste said through her breathing as they slowed out of the run. "You haven't lost any of your edge."

"Maybe," Faith replied, breathing a little harder. She was definitely out of shape. "Being back after six weeks isn't exactly a run in the park."

"Fair enough," she agreed. "As long as you're warmed up, want to do some sparring?" She shrugged when she rolled her eyes. "Yeah, it was Merc's idea. Keeps you on your toes."

They took a small breather, sipping some of the water Celeste had graciously brought with her, then moved to an open area of the finished roof. The area was enclosed by a roof access shed and some AC units, making a lopsided but perfectly functional sparring ring for them. Celeste squared off in a casual boxing stance, legs apart and hands loose, but defensive.

"You want me to go easy on you?" Faith teased, mimicking her position.

"You're the one who's been out," Celeste replied, stretching her arm across her chest. She ran her hand over her quiff, smoothing it down after the run. "I should be asking you that."

"Please, after I caught you that quickly?"

Celeste smiled and threw the first punch. Without safety gear, the best they could manage were courteous little trade offs. Faith had sparred her in full contact, and the punch she struck with now was nowhere near as fast or hard as it should be. She countered it easily, throwing a mock palm to the nose, which Cel blocked and turned into an arm lock.

They went back and forth, gradually increasing the pace until it matched a light jog, spliced with grunts of efforts. Only a few blows landed, light enough to shrug off as friendly taps. Neither of them had a preferred style; it was all a jumble of moves taken from the internet and surveillance footage from martial art schools, mixed in with what they saw in the movies. None of it was a clear discipline, and like running, often changed with the flow of movement and opportunity.

The sparring match ended with no clear winner. Cel was quick on her feet, once again her elegance showing through in her style. Faith was a little more heavy-handed; a punch was a punch, a kick was a kick. The faster and harder she hit, the faster she could get moving again. By the time they agreed to punch out, each of them had a few sore spots and were back to sweating profusely.

"Check this out." Celeste dug into the pack she wore at the small of her back a few minutes into their water break. Faith was surprised to see a gun in her hand. "A little something Kreeg and Drake worked up. New training model, based off of the standard CPF sidearm."

"Cool," Faith admitted as she tossed her the gun. The weight felt just about right. If it wasn't for the fact she checked the magazine and found a single dummy round in it, she would swear it was a real gun, not some cheap look-a-like made of wood or plastic. She tossed it back to Celeste. "Disarms?"

"You know it." She held the gun up. "Grab it."

As soon as she said it, Faith darted forward, grabbing her by the wrist, then grabbed the gun itself and twisted it out of her grip. Just as quickly, the gun was up in a firing position in her hand.

"Alright, how about one more time, this time without me handing it to you," Celeste said icily. Faith grinned in return and tossed the fake weapon back. "Wait for the snap this time."

She took a step back, waiting for Celeste to draw and aim like a cop would, and when she did, it was just as fast. This time Faith stepped inward, controlling the center between them, using Celeste's own momentum against her to sweep the gun up and over, and then pry it free. She even added a faux-strike to the back of her neck for good measure.

The two traded techniques back and forth for the next half an hour in the afternoon sun. Celeste didn't have any new techniques for her, but Faith was a fan of rehearsal when it came to hand-to-hand, going over the fundamentals and reliable techniques of what she knew would work.

A gentle hiss of static suddenly sounded in her ear as Celeste finished one of her disarms. "How's it going ladies?"

Faith lifted a hand to her earpiece, Celeste trading the gun to her other hand so she could do the same on hers. "Hey Merc. Good to be back."

"I bet. Listen, I know you guys are having the time of your life, but Drake's been riding my ass all morning. Cel, he's got some work for you that needs doing this afternoon."

"Yeah, I know. He made that more than obvious last night before I took off," she said with a roll of her eyes, then looked at her. "Workaholic. I gotta get going Faith. See you around!"

"Want to grab lunch later?" Faith called after her as she jogged across the roof.

"Sorry, rain check!"

After that, she hopped to the next roof, slowly turning to a red and blond blotch that skimmed across the featureless blue, white, and gray rooftops, before vanishing altogether.

"What about you Faith? Want to stick around for a bit? I got some things that you could do too."

"Let me at least grab some lunch Merc. I'm starving after that workout. I'll let you know when I'm done, okay?"

"Sounds good, kiddo."

Faith stretched her arms, turning to the direction of the Financial District. It had some good quick food places street level that she could get before Merc put her to work. The sun was still shining, and it was her first day back on the rooftops for almost six weeks. She broke into a jog, then a gentle sprint, and lost herself in the Flow.