Ruy Blas, one of Don Salluste's lackeys, falls in love with the young Queen of Spain, Maria de Neubourg. Spurned by the Queen, Don Salluste takes revenge by introducing her to his bright young valet, Ruy Blas, whom he has disguised as his noble cousin Don Cesar. When the queen falls in love with Blas, Don Salluste humiliates them both by revealing the handsome young man as his lackey. Blas kills Don Salluste to save the honor of the queen, then drinks poison and dies.