At the beginning of the film, there is a young man who decides to become a soldier to defend Mexico from an incoming invasion of the French army. After enlisting, he fell in love with a young lady, but it turns out that she is the niece of the French ambassador to Mexico. In one battle where the Mexican forces were near the brink of defeat, the soldier, Luis, decides to grab a trumpet and play the song "Mexicanos, al grito de guerra", the National Anthem of Mexico. Upon hearing the anthem played, the soldiers rally and overcome the French forces. However, Luis is shot and dies in the end at the same time his love escapes imprisonment.