The 1910 Mexican Revolution is on its way when six brave peasants, known as "Los Leones de San Pablo", decide to join Pancho Villa's army and help end the suffering in their community by assisting in the struggle. Together, they will endure the tragedies and hardships of a civil war.
In a Gothic-styled monastery, a monk named Javier sees the face of another monk, Juan, and suddenly attempts to bludgeon him to death with a heavy crucifix. Both men then relate their own versions of a story of romantic rivalry between them.
Camelia, a prostitute who works in a low-class cabaret in Mexico City (called "The Blood Stain') meets Guillermo, a young man from the country who just arrived in the city looking for a better life. She offers to take care of him until he gets set up, and the initial friendship soon turns romantic. This inevitably causes problems with Gastón, Camelia's pimp.
