Seth's wings.

Seth hissed in pain as the old man pried the red and swollen skin away from the broken shards of all that was left of his right wing. The blood had long ago dried into a thick scap, and it was rather unpleasant to have that scab broken open.
"Sorry.." the old man said hesitantly. With a reassuring look from Sala, he kept going. Seth was still a bit of a mystery to the people of Neo New York, him and his mother both. They weren't quite as feared as they had been the first day they walked through the Gates, now that Sala had talked to the city's Elders and got their tentative acceptance of the two Desert Walkers. But the people of the city were still wary of the two, stories still circulating about the 'demon and his mistress'.
The old man gently picked away the last of the broken shards of bone that were no longer connected to the root of the wing, which grew out of the shoulderblade. Seth's other wing was draped over the other side of the room. It's once pure-white feathers were now a dismal gray and wilted, a good number of them having already fallen out. It was dying without its partner, and Seth knew there was limited time to get a surrogate in place, or else he would have no choice but to remove the remaining wing as well.
That was why he'd come to this old man. Not only was he the best doctor and surgeon in the city, but he was known for prosthetics as well. While he'd hardly ever done anything remotely like what Seth was asking him to, he'd risen to the challenge. He surveyed the injury a last time, then rose to his feet and went into a room off the one they were in. When he returned a few moments later, he carried a contraption that looked remotely familiar, though it was all folded up and its shape wasn't quite discernable. It was made of sturdy aluminum poles that wouldn't bend, but were hollow and light-weight. There were joints that allowed it to fold up as it was, and Seth could only assume he'd made use of the hollow poles to attatch the mechanism that would allow his muscles to move the wing. Then, of course, the most important part of the wing was the lightweight canvas that was stretched like a sail over the poles. He motioned to Sala to hold the tip of the wing, while he walked to the other side of the room and let the wing stretch out.
Seth's eyes widened as he looked at the mechanical wing. He could even feel his real wing perking up, as if it sensed a new partner. "Well, I'll be damned... You really did it..da Vinci's wing..."
"With a few changes, yes." The old man smiled, glowing in the obvious praise Seth was giving him. He folded the wing up again and made his way back over to Seth. "This may hurt, son. The skin's still raw, after all."
"I'll be fine. Just do it." He exchanged a look with Sala, who smiled encouragingly to him, causing him to smile back.
The old man shrugged faintly and, as gently as he could, rested the chassy of the contraption over the wound. Seth let out another hiss as it settled over the bone and muscles. "Sala, come and hold this still."
She nodded and placed his hands where his had been, holding it as still as she could. "How will it work?"
"Well, there are sensors that will respond to the muscles in his shoulder, and I'll be attatching something to the base of his real wing, so the two can move in unison while in flight." He began to strap the thing into place around Seth's chest and back, making sure it was secure.
Seth's brow rose as the old man spoke. "You mean I'll be able to fly again?"
"That was the purpose of da Vinci's wing design, wasn't it? Flight? It's the same weight and relatively the same size as your other wing.. I imagine you'll be able to get off the ground with it. Maybe no fancy maneuvers, but it should hold up under a good glide, maybe a little more. You're not going to be a Walker anymore, right?"
Seth was quiet for a time, thinking over that question. His gaze drifted back to Sala, who looked at him curiously, even hopefully. He smiled, faintly, and nodded. "I guess not."
The old man just smiled as he finished hooking the controls up to Seth's other wing. "All right. That should do it. Try it out."
Seth sat up straighter, flexing his shoulders first, before slowly extending his real wing. At the same time, the mechanical wing slowly began to extend. Before it even got halfway, though, Seth let out a third hiss of pain and folded them both back again, hand instinctively lifting to grip his right shoulder.
"Hm.." The old man tapped his chin thoughtfully. "Guess you'll need to take it easy. I imagine the shoulder will need to heal and get used to the weight again before you can do any real work with it."
Seth slowly relaxed and sighed, letting his shoulder go. "Only to be expected. At least it works.. And my wing seems to be happy about having a new partner." Sure enough, some of the feathers on his pitiful-looking wing were a few shades lighter, looking healthier. "There's hope yet, eh?"
Sala smiled her relief, stepping forward to take the old man's hand. "Thank-you so much."
"Not at all, Saleem. Now both of you, get on out of here. I've got real patients to see."
Seth got to his feet, surprised and quite relieved to hear the old man joke with them like that. It showed he was growing more comfortable in Seth's presence, and that was a very good sign indeed. He slipped his hand into Sala's as he waved good-bye with the other, then led her out of the building back onto the sandy street.