Or the one where Wagner discovers a chorus and everyone dies.
The Norns can no longer see everything that has happened, is happening or will happen and know that the end is near. Meanwhile, Alberich’s son, Hagen, manipulates Gunter and Gutrune in order to meet his own ends – the ring. Hagen drugs Siegfried into finding Brunnhilde to marry Gunter, and marrying Gutrune. Brunnhilde states that she and Siegfried are already married, a fact that Hagen manipulates by forcing him into a contract he is unable to honour. To celebrate both weddings a hunting trip is arranged for the next day.
Out hunting the next day Siegfried is approached by the Rhine Maidens who seek to regain the ring. Siegfried gives it to them freely but they see that it is still cursed and until the curse is removed it is useless to them. Siegfried is drugged (again) and begins to tell the tale of how he and Brunnhilde met. As he remembers his first (and true) wife he is stabbed in the back by Hagen.
Wracked by grief, Brunnhilde commands that a pyre be built to burn Siegfrieds body and curses the gods to share in his fate. Hagen is killed by the Rhine Maidens (who reclaim the ring) and Brunnhilde jumps onto the funeral pyre with Siegfried and the gods are destroyed.
How can fifteen hours be over so quickly? It seems like barely a fraction of that time and far less than it should be. I was in tears come the end, as was much of the rest of the audience. Forget whatever preconceptions you have about Wagner (variously; long, boring, or a nazi) at the heart of all of this is a very simple tale of doomed love. Die hard romantics would be best to stock up on tissues beforehand though.