Alain, a doctor, has had his life turned upside down by a family tragedy. To forget, Alain joins the Foreign Legion. With the support of his captain, he wins the trust of the caïd Ben Hadj, heals and saves the latter's son, and falls in love with Kadidja, whom the caïd has entrusted to his care. Ben Hadj fights against the rebels, but sees his friend Alain die. Kadidja emerges to avenge him.