Medical Investigation

As the drama that began on "Third Watch" continues, the rest of the team joins Conner and Natalie in New York as they race against the clock to determine what the deadly virus is that has landed paramedic Carlos Nieto and the robbery suspect that he was attending to in the ICU. Conner teams up with Detective Faith Yokas to search for the robber's accomplice, whom they hope will lead them to the source of the disease. Meanwhile, Eva tries to console Holly as she waits to learn if Carlos is going to live or die. As more infected people arrive at the hospital, the team must race against time to track the source of the mysterious illness before more patients die.

When a Congressman, a lobbyist and a Capitol police officer are stricken with a mysterious disease, Dr. Connor and his NIH team fear a terrorist plot, until the leader of a prostitution ring becomes the fourth victim. An uncovered list of "clients" turns up a "Who's Who" list of leading Washington figures, forcing the team to walk a fine line between politics and protocol to contain what seems to be a deadly STD. Meanwhile NIH Director, Dr. Ewing and Eva fight to keep the story out of the headlines. As the death toll increases and a blood test yields unexpected results, Connor's team must search for clues in the unlikeliest of places.

In the first part of the season finale, Dr. Connor and his team confront their greatest challenge when they enter a violent Central American country to combat a mysterious disease. Their efforts are further endangered by a massive new earthquake -- and a murderous jungle insurrection that has Connor, Miles and Frank held hostage. Elsewhere, Dr. Durant struggles to salvage lives in a wrecked clinic and isolate the deadly contagion while Eva tries to help an isolated and terrified boy.

In the concluding half of the season finale, Dr. Connor and Frank are taken prisoner by rebels in a Central American country wracked by a meningitis outbreak and a deadly earthquake -- but the pair convinces the squad's leader (as Baracas, guest star Jesse Borrego) that his missing sons are trapped with Dr. McCabe in a ruined mission. As they work together and hope to arrive in time, Dr. Durant and Dr. Ewing fight a swelling meningitis epidemic that threatens a young mother and baby while much-needed supplies are hijacked. In addition, a sympathetic Eva can't ignore a forlorn boy who lost his parents in the temblor.