Lexa's suspicions lead Mutant X to unveil a traveling death camp, which is posed as a circus for mutant refugees and Mutant X's enemy within the Dominion.
Discovering that their teammate Lexa is the subject of a covert experiment that is controlling her, the Mutant X team hunts for the doctor responsible.
Mutant X unearths an old military experiment involving an age-reversal serum and is surprised to discover that Jesse's grandfather is a one of the test subjects.
In the aftermath of disaster, the Mutant X team must deal with the death of one of their teammates, the disappearance of another, the return of Mason Eckhart, and the arrival of a mysterious mutant with an agenda of her own.