Three interconnected stories about the different strata of life in Mexico City all resolve with a fatal car accident. Octavio is trying to raise enough money to run away with his sister-in-law, and decides to enter his dog Cofi into the world of dogfighting. After a dogfight goes bad, Octavio flees in his car, running a red light and causing the accident. Daniel and Valeria's new-found bliss is prematurely ended when she loses her leg in the accident. El Chiro is a homeless man who cares for stray dogs and is there to witness the collision.