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.