We descended the stairs from the throne room into the main entrance hall, intending to ambush the unaware cultists who were levitating around the hole in the floor through which the wind was rushing.  We split up so that some of us came down one stair and some down the other.  As subtlety and stealth were called for, Alleria and I took the lead.  She jumped from shadow to shadow until she was behind a pillar near the hole in the ground, and then cast silence over the group centred on the high grade cultist of the grade that had lightning bolted us a the week before.  I then dashed forward and cast a web spell than trapped the same cultist and his nearest companions in a mess of sticky strands.  Feyabelle started up her normal hail of arrows, targetting the highest grade cultist first and working downwards.  Thorg rushed forwards and decapitated a low grade cultist with a single blow, and then proved unable to hit anything for the rest of the combat; so focused on the power of his blows that he forgot about accuracy.  The fight was mercifully relatively brief – the high level cultist never got free of the web and was killed by Feyabelle’s arrows before he could do any harm.  One cultist made a bolt for the far door, but Alleria caught him before he could escape.  My frost rays finished off a few of the cultists.  As usual for cultists though, they had no treasure on them at all.