Directors Heidi Specogna and Rainer Hoffmann most artfully capture the marrow-deep passion of the guerrillas in 62-year-old Pepe Mujica. Still the picture of rebellion with his silvery mane and motorcycle, the flower farmer/parliament representative weaves arresting anecdotes about his political past, including a brutal 13-year imprisonment as a hostage. The scene in which Mujica visits the prison site, now a gleaming shopping mall, unsettles with particular poignancy.

The documentary relishes such bittersweet ironies, framing the Tupamaros' tales with postcard-pretty Uruguayan tableaux. Although the film's presentation of the group's early days is fuzzy, it limns the Tupamaros' current state of flux with stinging clarity: their Robin Hood days are over. As the rough-hewn Mujica admits to being more of a figurehead than a force among the suits and ties of parliament, he's the very definition of a rebel without a cause.