This is the final installment of Wagner's Ring Cycle. The final Immolation Scene has already been Legoed, so this is a scene from Act One. Siegfried arrives in Gibichung Hall to meet Gunther (who I imagine is surrounded by hunting dogs). Gunther's sister Gutrune, who as Anna Russell points out is the only woman that Siegfried ever meets who is not his aunt, prepares a fateful love potion.
Read more about this opera here.
Listen to the recording here.