A partially liquefied body is found in a biohazard waste bag, mixed with veterinary waste, and possibly infected with some virulent new pathogen. The CDC puts the Jeffersonian on lockdown as the CDC try to figure out if there's a danger of a deadly viral outbreak. Dr. Ivan Jacobs of the CDC is hoping that the Jeffersonian team can identify the victim, and that learning the victim's identity will determine where she contracted the infection. However, it soon becomes clear that somebody didn't want the victim identified: the skull was deliberately crushed to avoid an ID from dental records. With no tissue left for fingerprints, the team hypothesize that the killer knew exactly how deadly the disease was... and that he may be a bio-terrorist.
Still, Angela, with Brennan's help, manages to ID the victim as Mia Garrett, a blogger-journalist with a focus on big pharma and medical research whose boyfriend says she was onto a big story... one she wouldn't discuss with him. Suspects include Mia's boyfriend, a scientist she recently interviewed who is an expert on mutating pandemics, and a man Mia was investigating for doping thoroughbred horses so they'd win races. Meanwhile, Arastoo is cut by a micro-needle on the body – which apparently caused the victim's infection – and becomes infected himself.
As Cam worries, Arastoo heroically volunteers to remain at the Jeffersonian so they can study him as the disease begins its work upon him, in hopes it will help the CDC identify the virus. Brennan realizes that whoever mutated the virus probably also created an antidote to keep them safe from their own creation, so saving Arastoo's life from the disease's terrifyingly fast onset depends on them catching the killer.