Session 35: Battle with the Frost Druid Cultists

Having dispatched the Frost Giant Skeletons AND triggered the trap on the lair of the long dead Frost Giant Queen, the party makes there way toward the only remaining door in the basement level where they encounter several Frost Druids. A battle ensues in which all but one bring their considerable powers to bear. The one seems distracted by a spell casting but what could it be summoning?