Following the rescue of Lady Hillibrand from the vampyre dungeons under the royal tower, Father Pat is summoned to discuss the events under the castle by Garek, Royal Advisor to the young Duke. Meanwhile, Porkins and Clinton are hired by Lady Hillibrand to steal the remaining gate crystal in Tyn, which is held in the Royal Mint- one of the most secure locations in the city. Fritzel is left at their disposal as Porkins finds and hired Finneran Four Fingers, an old acquaintance dating back to the party’s first adventure.
Back at the Royal Tower, Garek explains to Pat that although his actions seem traitorous to some, he is merely acting to protect the Duchy with actions such as pushing for peace with Verma. He informs Pat that the Duke is launching an inquisition to get to the bottom of the Vampyre infestation, and suspects one Earl Chesper, who requested moving Dominion prisoners to the dungeons in the first place. Pat wants to leave the tower but is heavily pressured by Garek to stay for the inquisition to inform the court of the events.
Meanwhile, Clinton and Porkins have formed a plan to steal the gate key, using maps and information provided by Fritzel, who helped design the original version. With FInneran’s help, they prepare to set their plan in motion when Golden Boy stumbles upon them and informs them that the Adventurer’s Club has been raided by Tyrese guards, who have captured Peloquin.
Back at the Royal Cathedral, Radcliffe has awakened from a fugue state that seems to have been brought on by wearing the Coral Crown in the vampyre dungeons. Lady Hillibrand brings him up to speed, informing him on the wearabouts of his friends and the fact that Kile the Unkillable has returned to the dungeons to investigate an apparent residual evil lurking under the vampyre crypts, with the help of his men and several battle priests. Meanwhile guards arrive, demanding both of their presence at the Inquisition.
At Royal Hill, Clinton and Porkins put their plans into action. Fritzel informs the Mages Five that the party has given him the Coral Crown for safekeeping. Guards arrive to store the Crown in a lead box, which has been loaded with an invisible Clinton, disguised as a monkey. The plan is almost thwarted but guards are distracted by Finneran’s wenches. The guards bring the storage box, with Clinton inside, into the vault. Once there, Clinton finds the key (and other random items) but triggers an alarm which drops the entire vault into a cistern of water, flooding it. Clinton turns into an octopus and escapres with the crown and the gate key.
Meanwhile, as the inquisition starts, Earl Chesper and Garek put forward their arguments on how the prisoners were originally assigned to the dungeon, while Pat and Radcliffe posit that the vampyres were there beforehand and changed the prisoners into vampyre spawn. Suddenly, the face of the bored young Duke is overlaid with a ghastly face, claiming to be Baron Rottli, revealing the evil presence in the very court.
While the Duke’s main priest transforms into the evil Fighter-Wizard Thraxus, wielding the obsidian Scythe, the Yound Duke’s body becomes distorted and the face of a foul woman, with the body of a black serpent, emerges from the boys mouth, shedding him like a skin. Thraxus kills Earl Chesper and the bailiffs instantly with his Scythe.
While Radcliffe, Pat, and Peloquin and Lady Hillibrand battle these threats, Clinton and Porkins use the Gate Crystal at the Lightning Gate under Royal Hill, which creates a connection to the Aperture device in Pallmoor Gates, allowing Earl Hillibrand and his men to come through it. As those men proceed to the tower to root out the true evil, Clinton tries to remove the crystal but is unable. Rapidly, the gate seems to overload with energy, and the Astral plane appears about to invert into the material plane, with ghostly landscapes appearing about them, when Clinton smashes the crystal which also destroys the gate.
In the tower, the remainder of the party battles Thraxus and the Naga to a standstill, with the Naga casting a lighting bolt which kills Peloquin.
At the surface, Clinton, Porkins, and Golden Boy discover that a giant, hellish purple worm has emerged from under the Royal Tower and is smashing it. They commence to attack the worm while Fritzel mans a ballista, but the worm swallows Clinton in the process, and destroys the base of the tower.
As the tower collapses, Thraxus uses his scythe to teleport away, and Father Pat is rescued by Golden Boy as the tower falls around Radcliffe, protected by a resilient sphere. Lady Hillibrand is saved by her ring of Feather Falling, but the tower has apparently taken out Earl Hillibrand and his men.
Clinton, inside the worm, is finally able to kill it with a flame strike as the tower falls around him.
Days later, with the Duke Robilard, Chesper, and Earl Hillibrand dead or missing, the Lady Hillibrand is crowned Duchess of Tyn, which she claims is temporary until others are rescued. Sir Kile is still missing as well, as is the body of Peloquin. Lady Hillibrand holds a short ascension speech in the ruined courtyard, when the crowd murmurs about events in the harbour. Climbing the ways, the party sees that hundreds of Dominion ships- the damaged remainder of an invasion fleet, have somehow made it into the harbour. Floating in from the sky, the Dominion Sorceress, Limynsa, declares a formal partnership with Tyn for the purpose of destroying Baron Rottli once and for all.