A girl sits alone on a bench in a quiet suburban yard, looking hopeful. A young woman in a sequined minidress has joyless, anonymous sex in a nightclub bathroom while music pounds overhead. Soon it’s clear that we’re looking at the same person 15 years apart, and that the chasm between them has a name: Ray. It would be an ugly stretch to call Una — adapted by Scottish playwright David Harrower from his own 2005 two-hander Blackbird, revived last year on Broadway with Jeff Daniels and Michelle Williams — a love story, though it does portray the fevered relationship between a much older man (Ben Mendelsohn) and the 13-year-old he seduces (played by Ruby Stokes and later Rooney Mara) without cleaving to a straightforward narrative of predator and prey.
After finding a picture of Ray — who has moved, remarried, and changed his name to Peter — in a local paper, the grown Una decides to pay him a visit. He’s rightfully panicked; she’s not easily ignored. Director Benedict Andrews adds new settings and characters, including Riz Ahmed as a kind bystander drawn into their chaos and Tobias Menzies as Ray’s peevish boss. But the movie belongs to Mendelsohn and Mara, two caged animals circling. Una’s raw, deeply discomfiting dance between obsession and exploitation isn’t easy to watch by any metric; they make it hard to look away. B+