For the first third of the film, there's no clear protagonist. We rove into the POV of activists as they hold demonstrations at the offices of a pharmaceutical giant and in a local school, spattering walls with fake blood and passing out condoms to kids. Campillo presents them as an indivisible group, working in unison, faltering and then quickly righting their ship, before he focuses on the developing relationship between two men, Nathan (Arnaud Valois) and Sean (Nahuel Perez Biscayart).
Quiet, handsome Nathan is HIV negative, while the boisterous Sean is "posi." The first night they spend together, Sean reveals that his high school math teacher transmitted the virus to him -- it had been Sean's first time. Nathan, on the other hand, just got lucky. Sean is so very alive in every frame -- with every moment to speak, to kiss, to crack a wicked joke seized -- and yet we know he will almost certainly die. As they lose themselves on a dance floor, BPM makes their present so thrilling that we don't focus on what bleak future may await them.