From the introduction:
Mutation. It is the key to our evolution. It has enabled us to evolve from a single-celled organism into the dominant species on the planet. This process is slow and normally taking thousands and thousands of years. But every few hundred millennia, evolution leaps forward.
Well, no, not really. But that's apparently how things work here, and it had furthermore given birth to people with superpowers. Recently, mutants have been put more and more in the spotlight. And, as always, humanity has struck out against those different from them, with many calling for them to be hunted down and rounded up, and many mutants retaliating in kind.