On the 25th anniversary of the first diagnosed cases of AIDS, FRONTLINE examines one of the worst pandemics the world has ever known in "The Age of AIDS." After a quarter century of political denial and social stigma, of stunning scientific breakthroughs, bitter policy battles and inadequate prevention campaigns, HIV/AIDS continues to spread rapidly throughout much of the world, particularly in developing nations. Part One's two-hour broadcast begins with the medical and scientific mystery that emerged in 1981 when five gay men in Los Angeles were diagnosed with a new disease. It traces the international response in the first years of the epidemic, contrasting moments of inspirational leadership with the tragedy of missed opportunities. The film also reveals the astounding spread of the disease to over 70 million infections in 2006. Part Two explores the chasm that emerged between rich and poor following the development of the miraculous "triple cocktail" HIV treatment in the mid-1990s. While the treatment seemed to signal a new era in which AIDS was no longer a fatal disease, the high price of the drugs meant they were unaffordable to patients in developing nations. The film also examines the next wave of the AIDS epidemic in some of the most populous and strategically important nations in the world, including Russia, India and China, and tracks the same pattern of official denial and political indifference that characterized the epidemic in so many other countries.