What is happening to Katherine?
Someone put something into her at the plasma center and took it back out again. By the time her friends catch up to her, she's not exactly the person they remember. She has begun to change into something new, and if they're going to help her escape the people who did this to her, they may need to transform, too.
Squarely in both the crime and body horror traditions, Mutant Circuit reads like Elmore Leonard and David Cronenberg meeting at 3 AM in a run-down strip mall parking lot, and Mark Jaskowski is the conspirator who brought them there.