From the publishers blurb: High above the snow line there is a castle on a crag. It is an object of fear and hatred, because the Heartless Queen holds court there and she is pitiless in her anger and host to terrible friends. Between the Frost Wyrms, the Ice Harpies, and the Frozen Thing that Guards the Bridge, even getting in is difficult. Most locals stay as far away as they can, but between courage, pride, and burning vengeance there are always some willing to take a shot at it. And travellers from the soft, warm south might hear stories of the Queen’s fantastical treasures and be oblivious about the horrors that protect them. Player characters may have many reasons to interfere with the castle, and this thus constitutes an adventure location for the Old-School Essentials rules, for 5-6 PCs of 3rd level or slightly fewer of 4th.