Vestige

Supposedly trying, as so many governments do, to better protect their people, the American military began a program to introduce super powers to volunteers. In the early years, the program appeared to be a success, but it eventually became clear that those involved were beginning to deteriorate with time. Not only that, but the effects prove to be contagious like a disease. With bodies and minds warping from a procedure they know little about, many 'superheroes' have rebelled and the world has gone to ruin in the chaos.
The cities, after initial panic and carnage, were fled. There is only ruin and the once-heroes who wait and hunt for those who carry the disease, thinking it their responsibility to eradicate it. Supplies are most plentiful here, yet not worth seeking for most.
Those uninfected who escaped the initial massacres of the cities fled to gated communities and country towns far from metropolitan areas. They're typically well guarded and unfriendly to strangers. Sometimes they struggle to produce and scavenge enough for their people, but many have learned to be self-sufficient with farming and even livestock.
Finally, the In-Between. Anywhere between the cities of the fallen supers and the small towns of survivors are camps full of infected drifters with nowhere else to go, carrying an evolved version of the disease that spreads exponentially faster. Many are the children of the military men and women who volunteered for the original program, some are original volunteers who never agreed with the idea of eradication. They live in tents, in abandoned houses, in the fringes of the cities, typically in small groups. They take care of each other, for they are hunted, and they've typically lost everyone else.
Asher is at the center of one such group of Evolved carriers. His older sister deteriorates alarmingly from the procedure she'd volunteered for, and he has to rely on the power she infected him with to find a cure. It's all the help he has, aside from Angelika and Mikhail, the only other people he's ever cared about.