Underground is a film about the Weather Underground Organisation—a group founded as a militant faction of the civil rights and anti-war movement of the 1960s and 1970s. The film combines interviews with members of the group after they went underground who explain how they became radicalised amongst the political happenings in the United States at the time, as well as the revolutionary struggles in Cuba, Russia and China, and the history of struggles over Native American rights and labour issues. Also detailed is the group's analysis of American society, addressing those who have inspired them, and further explaining the reasons behind their militancy, while also introducing the issue of tactics. We see the use of property destruction as a way to bring about change and destabilise the current political order. Underground takes an intimate look at the inner workings of the Weather Underground and their strong internal collective identity, providing a record of how a bunch of middle-class Americans became self-styled militant revolutionaries, raising questions not only about the merits of their struggle, but also about past and future radical actions.