Debuting writer-director Fran Kranz's years as an actor show in the powerful performances he draws from his tight ensemble in Mass, a drama of searing intimacy that trades the political for the personal in its reflections on gun violence and mental health. With laser focus and unflinching emotional candor, the film approaches the seemingly unending horror of school shootings in America from the viewpoint of devastated parents on both sides of the tragedy, six years later.