Tuberculosis was once thought to be a disease of the past. But with virulent new drug-resistant strains emerging faster than ever, TB — passed simply by a cough or a sneeze — is the second leading cause of death from an infectious disease on the planet. In TB Silent Killer, FRONTLINE presents an unforgettable portrait of the lives at the pandemic's epicenter. Families battle the spreading strains of Tuberculosis in the Southern African nation of Swaziland.