Die Walküre is the second of the four Ring operas, introducing Brünnhilde, daughter of the all-powerful god, Wotan. Brünnhilde's attempts to protect the siblings/lovers Siegmund and Sieglinde eventually lead Wotan to encircle his errant daughter with a protective ring of fire that only a hero will be able to penetrate. Die Walküre features the best-known excerpt from the Ring cycle, the Ride of the Valkyries.