This is a nonfiction film released last year about two events in the Communist Party of Brazil (PCdoB)'s history: the Araguaia Guerilla War, an armed struggle with the government from 1972 to 1974, and the Lapa Massacre of its leadership in 1976, made by and for sympathizers of 70s Maoist PCdoB ideology. It's on Youtube in 1080p, but there are no subtitles. Even if there were, it wouldn't be worth your time to watch.

The Youtube video has only a few hundred views and its exhibitions had similarly limited audiences, mostly (maybe exclusively) in universities. Debates were held by the people interviewed in the film prior to some of the exhibitions. The authors assume viewers are already familiar with the subject matter and instead focus on less known details of the Party's evolution, so I'll give a brief description.

The Party wished to overthrow the military government through a Chinese-style peasant revolution and picked as its starting point a large stretch of land in the eastern Amazon on the middle reaches of the Araguaia River, 1800-1900 km away from São Paulo/Rio, north (downstream) of Brasília, south (upstream) of a state capital, west of the Amazon's border with arid biomes and east of the Amazon at large. This area was populated by impoverished recent settlers who were left behind after mining operations were shut down.
PCdoB's leadership gradually sent its best cadres to the region from 1967 onwards, ultimately building up a strength only in the dozens of militants. Logistical connections were made to the country's core. Cadres took up codenames and trained for jungle warfare. They provided health and educational services to the locals and attempted to blend in; nonetheless, the peasants treated them well but fully realized that the newcomers were highly educated urbanites from the nation's core. At this point there was still no attempt to convert the peasantry to Marxism. Guerillas were divided in three detachments: A, along the Transamazonian highway, and B&C in hills to the south.

By 1972, authorities learned of the guerilla cell's existence. Federal Police investigators arrived in the area to ask about newcomers, but the Party dismissed their threat, as other leftist groups also existed throughout the Amazon. They were caught by surprise with the sudden and unannounced arrival of 1500 troops from April to August as part of operation Papagaio. Peasants who traded or collaborated with the communists were arrested and monetary rewards were offered for information. Some peasants -the bate-paus were enlisted as guides and informants. Others backed or even joined the insurgents. Friendly fire incidents happened due to poor coordination. The military was unprepared for fighting in the jungle and this offensive died out by August, with only detachment C identified and few guerillas eliminated. But this heavy presence did dissuade Party leaders from arriving in the area with reinforcements and further instructions, ultimately cutting off the insurgents from supplies and contact with the Politburo. A renewed offensive was made in September with a hearts-and-minds approach to the local population, but was equally unsuccesful. Troops were evacuated from the area in October.