Where Das Rheingold introduces us to the gods, underworld denizens, and giants who inhabit the world of Wagner's Ring cycle, the second of the four operas, Die Walküre, focuses on the interaction of men and gods. The turbulent orchestra brings Siegmund, Wotan's earthly son, into the home of his vicious enemy, Hunding, whose wife Sieglinde turns out to be Siegmund's newfound lover and twin sister. The gods meddle in their showdown battle, with Wotan bowing to his wife Fricka's demand that he uphold the sanctity of marriage by allowing Hunding to win. Wotan's favorite daughter, Brunnhilde, sides with Siegmund, earning Wotan's unbridled anger. She manages to shelter the now-pregnant Sieglinde, though, before being banished forever from Valhalla to a mountaintop ringed by fire. Like its predecessor, producer Harry Kupfer's Barcelona production of Die Walküre is spare and symbolic.