The Knights of Kenabres push on to Drezen but find the way blocked by a enormous vescavor swarm.
It’s ascertained that there is probably a queen below the surface in a honeycomb of caves. The heroes leave the army behind and head below. After fighting off a few smaller swarms they find the queen and manage to destroy her. They also find an Abyssal rift which they close just in time as a vrock tries to use it to transition to the material plane. The swarm disperses and, with the way clear, the army advances.
With Drezen nearby, the army camps and two curious events occur. Firstly, Andrei observes Nurah acting suspiciously (but can’t define exactly how) and follows her through camp only for her to give him the slip. The next morning, there is some strange behaviour from Aaron. After he is confronted, it is revealed by Sosiel that he is a Shadowblood addict and that he found several vials of the drug in his bag. Aaron claims that someone knew about his weakness and planted them there. The leaders decide to confront Sosiel, Aaron and Nurah in a zone of truth but come out none the wiser. If there is a traitor in their midst, they have failed to flush them out.