Bob is back. His brain surgery caused an infection which leaves him in a bad shape when found. He is put into a medically-induced coma. The team travels to Mexico where an antibiotic-resistant strain of TB is killing the Zapatista Revolutionaries.

Carlos has disappeared for two days and David goes back to Mexico first to find Carlos and second help the Mexicans to fight the drug resistant TB that is killing tens of Mexicans in the region. Mayko and Rachel work non stop to find a cure to the TB and to find what is causing the inhabitants of Hudson Point, Illinois to be insensitive to pain.

As if being HIV positive wasn't enough, Wes is infected accidentally with a needle full of Hepatitis C.

Bob continues to be haunted by memories of his time at Roth's secret lab; Wes insists that Rachel inject him with a highly experimental mutant red blood cells to fight the virulent Hep C; a mysterious disease that's causing brain inflammation in a small town appears to be contagious.

After an experimental treatment for Hep C nearly kills him, Wes quits NorBAC to enroll in a cutting edge HCV program in Stockholm; a racist city councilor claims his daughter was poisoned by Muslim extremists; the FDA is willing to fast-track some drugs in order to save an immune-deficient woman who was infected with smallpox.