The loss of Skyreach Castle in Hoard of the Dragon Queen was a major setback to the Cult of the Dragon, but still only a setback. The cult is determined to retake the castle and claim Tiamat’s lost treasure buried in its frozen walls and cloudstuff vaults, but they aren’t the only ones. Blagothkus the cloud giant is still the master of Skyreach, and he has gone to the hall of his cousin Brunvild, ice lord of Uldoveld, for the resources to repair and reoccupy the castle. At the same time, the party is dispatched by the Council of Waterdeep to reclaim some of the stolen treasures lost when the castle fell.
The Cult of the Dragon leads the charge in an unholy crusade to bring Tiamat back to the Realms, and the situation grows more perilous for good people with each passing moment. The battle becomes increasingly political as opportunities to gather allies and gain advantage present themselves, all centered in Waterdeep. Continuation of Hoard of the Dragon Queen.