In his latest uncompromising (nearly 3-hour!) film, the writer-director Carlos Reygadas and his real-life wife Natalia López play a married couple who own and operate a ranch for breeding fighting bulls in the rural Mexican countryside. They are cultured and literate people — he is also a well-known poet — and they have an open marriage. When the rules of this sexual arrangement begin to fray, so does the trust at the heart of their partnership.