Time Out says
Tragic romance turns downright spooky in Sebastin Cordero's suspenseful study of two immigrant Latin Americans struggling in a prejudiced, class-conscious Spain. Rosa (Garca), maid to a rich couple living in a musty mansion, enjoys a budding romance with hotheaded construction grunt Jose Maria (Parra). But after his foreman fires him for attacking a jealous coworker, our blue-collar hero accidentally becomes a killer.
It's tough to sustain sympathy for a guy whose temper leads to a second death before the film is over, but the dramatic imperative here is to turn Jose Maria into a fugitive who, unbeknownst to Rosa, takes refuge in the mansion attic. That's where the film starts to get interesting, and where the involvement of producer Guillermo del Toro (Pan's Labyrinth) makes itself increasingly evident: Suddenly, an otherwise pedestrian working-class drama becomes a fitfully affecting parable about social invisibility. Jose Maria can only watch from a distance as the woman he loves struggles in his absence and, as fate would have it, begins to plan her own family---and her own future---without him. More than a few moments feel implausible or overwrought; yet the movie, about two people so desperate to be alive, is eerily haunting.