David is more determined than ever to stop the birth of the first human clone after he has a chilling glimpse into the future.

Roth has given the world's most powerful leaders the stem cell treatment that Bob has discovered leads to violent paranoia. A horrific atrocity is uncovered as Carlos investigates a mysterious outbreak in Moldova.

Forensic evidence in the case of a young boy's murder leads the NorBAC team to investigate the existence of a prehistoric creature, believed extinct for 10,000 years. A dramatic development complicates NorBAC.s plans to deactivate Nina's Jacobson's Organ.

Disregarding procedure, David hires his new lover, Enuka. Mayko is contacted by the parents of a sick child who believe she is their last hope. Scientists must discover how to deactivate Nina's Jacobson's Organ as her behavior becomes increasingly erratic and violent.

A terrorist cell infiltrates the NorBAC lab and forces the scientists to produce a deadly measles mutation to be used as chemical warfare.

Bob finally tracks down Nina but makes a gruesome discovery at Roth's lab that suggests an experiment on Nina is about to go terribly wrong. The team investigates unusual crow attacks that appear to target military airports.

A pharmaceutical company comes under fire when its newly-marketed immune suppressing drug triggers a high incidence of congestive heart failure. David must find a replacement for Wes. Bob recalls romantic memories of a girl named Nina after suffering a stroke.

When a mysterious outbreak at the Tour Cycle Quebec hospitalizes several cyclists, NorBAC must investigate. Meanwhile, a controversial hyperbaric chamber treatment may help Bob manage his brain infection.

After an experimental treatment for Hep C nearly kills him, Wes quits NorBAC to enroll in a revolutionary HCV program in Stockholm. A racist city councilor claims his daughter was poisoned by Muslim extremists. The FDA is willing to expedite some drugs to save an immune-deficient woman infected with smallpox.

Bob is haunted by memories of his time at Roth's secret lab; Wes insists that Rachel inject him with a highly experimental decoy drug to fight the virulent Hepatitis C. A contagious disease appears in a small town, resulting in mysterious brain inflammation.

As if being HIV positive wasn't enough, Wes is accidentally scratched by a needle tainted with a genetically-engineered, virulent strain of Hepatitis C.

David returns to Mexico to find Carlos and to deal with the drug-resistant TB strain that has been killing the Zapatista rebels Mayko and Rachel get a lead in the mysterious outbreak in Hudson and Bob comes out of a medically-induced coma with little memory of what happened to him.

Bob is put into a medically-induced coma to reduce the risk of infection resulting from the brain surgery he received at the end of last season. David and Carlos investigate a drug-resistant strain of TB that is killing Mexico's Zapatista Revolutionaries. Rachel and Mayko travel to a farming community where citizens are suffering a rash of horrific injuries due to an inability to feel pain.