A catastrophic car collision in Mexico City connects three distinct stories involving love, betrayal, and dogs across different socio-economic strata. In the first segment, working-class youth Octavio (Gael García Bernal) enters the brutal underground world of dogfighting to raise money to flee with his pregnant sister-in-law, Susana (Vanessa Bauche), who is abused by his violent brother Ramiro (Marco Pérez). In the second segment, middle-aged magazine editor Daniel (Álvaro Guerrero) abandons his family to set up house with Spanish supermodel Valeria (Goya Toledo), only for their glamorous dream home to collapse into psychological torment when Valeria loses her leg in the crash and her pet dog becomes trapped beneath the floorboards. In the final segment, El Chivo (Emilio Echevarría), an ex-guerrilla turned homeless hitman who rescues Octavio's wounded dog, confronts his past as he contemplates a contract killing between two estranged half-brothers.