He knew that he would be facing an angry crowd, but he entered the 'lion's den' without hesitating.
the club's reputation as a 'den of iniquity' [=a place where immoral or illegal things are done]
He spent most evenings in the 'den' reading and smoking his pipe.
(..) Aegon built the wheel. If that's the kind of queen you want to be, how are you different from all the other tyrants that came before you? So we walk into the lion's den? My brother promised me he'd keep a grip on the Lannister forces. Forgive me, but I don't care about any Lannister promises. (..)2017 TvShow: Game of Thrones Title: Beyond the Wall Season: 7 Episode 6