The previous party are looking for treasure in an abandoned Dwarven settlement, like Thorin and his dwarves. Breya says something along the line of "We should have brought a burglar." (Bilbo was the burglar in The Hobbit). Without a burglar, most of the party in Avanchnzel die - if Bilbo wasn't with the Dwarves in the Hobbit, they would have died on several occasions.
