Province of Ciudad Real, Spain, December 29, 1990. During the annual march to the Herrera de la Mancha prison, held in support of the members of the terrorist gang ETA imprisoned there, the Basque rock band Negu Gorriak holds a concert, which is recorded, edited on video and turned into a tool of vindication. Decades later, a film crew tries to elaborate a personal essay around this event and its meaning.