Two identical murders, one on the East coast, one on the West. Two identical little girls, who may or may not be involved. Are these mirror-murders just a bizarre coincedence? FBI Agents Mulder and Scully don't think so. And when their investigation leads them to a DNA-splicing doctor who's been tinkering with the gene pool, they're faced with some terrifying questions. Why were these little girls created? Are they a product of a genetic experiment gone awry? Agents Mulder and Scully need to find out, before the next crop of killers is born..