A paid agent of Hitler's government ramps up a targeted propaganda effort aimed at weakening democracy and supporting the fascist cause in America. His base of operations... the center of American democracy itself -- the United States Congress. Sitting members of Congress, and the America First movement, take part in an elaborate scheme to subvert democracy. Laundering millions of pieces of Nazi propaganda through Congress and into the hands of the American people.

A devastating explosion rips through a munitions plant in a small New Jersey town. And the American public is left with the chilling fact that the federal government had been warned about such an attack almost a year prior. The tip had come from a private spy ring operating in Los Angeles that was intent on doing what law enforcement had largely failed to do. Infiltrate far-right groups plotting violence across the country, and foil their plots before it was too late.

The most prominent media figure in America calls for the creation of a militia, armed Americans willing to use violence to get their way. What they want is to overthrow the U.S. government and to end democracy in this country – by force. Their plot raised alarming indications that the federal government is not up to the task of dealing with that kind of homegrown threat.

It started with a plane crash. The tragic, mysterious crash of a commercial airliner in the summer of 1940 left a scene of devastation in rural Virginia -- and a series of unanswered questions. The cause of the crash was unclear. Among the dozens of people killed was a sitting U.S. senator. His presence on the flight and the strange circumstances surrounding the crash would end up revealing threats to American democracy itself.

Sitting members of Congress aiding and abetting a plot to overthrow the government. Insurrectionists criminally charged with plotting to end American democracy for good. Justice Department prosecutors under crushing political pressure. Rachel Maddow Presents: Ultra is the all-but-forgotten true story of good, old-fashioned American extremism getting supercharged by proximity to power. When extremist elected officials get caught plotting against America with the violent ultra right, this is...