The title of German Kral's documentary Our Last Tango suggests that it's about two people, which is reasonable considering how many it takes to do the title dance, but it's María Nieves Rego's story through and through. For a good half-century, Rego and her dancing partner, Juan Carlos Copes, were the biggest names in the tango world, except that much of it wasn't that good at all for Rego; as the almost-80-year-old says, if she had the chance to relive her life, "I'd do it all, except for being with Juan. "Obsessed with Copes as a teenager, she eventually married him, yielding a miserable union that produced no children and that continues to haunt the single and childless Rego. The philandering Copes eventually left her, but even after he remarried and started a new family, they continued to dance together; one particular performance qualifies as the tango equivalent of hate-fucking. Our Last Tango is very much about changing gender roles in notoriously macho Latin America, and Copes remains something of a cipher throughout. His attitude toward Rego is made clear when he describes her as his Stradivarius, and she acknowledges that too much of her self-worth was tied up in him, and she only now feels like her own person. Better late than never.