According to Mexican legend, the devil demands one soul be offered up for every bridge built, as a guarantee for the structure's durability. In Juan Carlos Rulfo's internationally-praised documentary, this age-old adage takes on mammoth proportions. Mexico City's "Second Deck" is a major architectural undertaking, an eleven-mile elevated freeway coursing through the center of the metropolis and impacting millions of lives. Among those affected by the project are the construction workers, who have helped transform the city. Director Rulfo crafts a deeply felt film about these men, the hands, hearts and minds behind a small universe of concrete and steel.