The fort is first seen when Valka is scouting to be sure her tribe wasn't followed. Grimmel the Grisly is flying over with his airship and calls his Deathgrippers back when they attack her. It's seen next when Grimmel is extracting venom from his dragons to make more darts in one of the open spaces just as Hiccup and the other Riders raid the fort in a effort to take him out. A battle breaks out and the stone tower is knocked over when the Goregutter crashes into it to revenge its rescuers. Ruffnut is accidentally left behind when the Riders leave. She's kept in a dragon cage while Grimmel and the Warlords scheme their next move. Ruff is eventually let go with a Scuttleclaw that was being housed in a cage next to her, which Grimmel hoped to track her to New Berk to find where the Berkians had settled.