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.