The medusa, it turns out, does not want to fight. Rather, she parlays with the party, making them an offer.
“We can help each other. I have been bound here in an ill-advised fey bargain by the Prince of Dusk. I have something you want,” she says, nodding at statues of Elder Druid Alrin, Isolde, and two others. “Kill the Prince for me, and I will release them.”
Silus and Shava bargain with the medusa, quickly securing the release of Alrin as a show of good faith, but not before the medusa intimates that one of the two unknown statues has information important to Chance. Alrin, grateful for being released, performs a ritual that refreshes the party and soothes their wounds before turning into a bird and departing.
“Who will seal the bargain with me?” the medusa asks, drawing a knife and holding it over he palm. Silus steps forward, cuts his own palm, and extends it. The bargain is made: the party will kill the Prince of Dusk, releasing the medusa; in return, she will free her prisoners. As an additional show of good faith, the medusa reveals the hiding place of a cache of treasure: a jade statue of a snake and a glaive, once of House Vashtar. In addition, she reveals that the door that she guards is warded by a magic door that responds to the answer to a riddle, as well as a deadly trap.
Armed with this knowledge, the party steps into the next room and up to the door. A portcullis slams shut over the other entrance and a demonic spirit appears.
“Welcome, supplicants,” it says. “You have reached the entrance to Vashtarborg. In order to proceed, you must provide the password. 'Pity the Emperor, for he wants what the pauper has. Pity not the pauper, for he has it in spades. Take it if you want, eat it if you wish, but if you do, you will die.'” With that, the walls start to move slowly inward, threatening to crush the heroes. Keeping their wits about them, the heroes quickly answer, “Nothing,” at which the walls recede and the door opens.
The heroes enter a cellar and ascend a flight of spiral stairs, coming up into the ground floor of the ruined mansion known as Vashtarborg, Sredin's ancestral home. They wander from room to room, finding most of it uninhabited, but eventually Shava hears voices ahead and the party proceeds more cautiously. Shava tells Kraygin that there are foes in the next room, and Kraygin kicks the door down and bursts into the room. Inside they find Kalder Red-Eye along with a number of his Mockers, prepared for the party's entrance.
Kraygin and chance rush in while the other stay just outside the room. Sredni lights a nearby table full of alchemical reagents on fire with a magic spell, igniting the reagents and starting a chain reaction that consumes half of the room and most of the mockers. It also, however, disturbs a magic circle of binding, releasing a creature of shadow and smoke. This creature is furious at having been bound for so long in Vashtarborg, and vents its frustration by hurling combatants around the room, into walls and into each other. Chance attempts to use a litany to banish the creature, while Silus uses his silver tongue to try to bargain with it instead.
Meanwhile, most of his Mockers having been incinerated and his lieutenant, Baris, having been pinned to a wall by one of Shava's arrows (and having been revealed as a doppelganger), Kalder Red-Eye senses defeat and runs. Kraygin catches up to him, though, and is quickly followed by Sredni, who wants Kalder's blood for defiling his home. Things calm down in the laboratory a little as Silus manages to placate the smoke-creature, buying the party a reprieve. They exit into the hallway to interrogate Kalder, who is more than willing to divulge whatever information they want.
Kalder tells them that he is merely a hired hand, and not truly loyal to the Prince of Dusk or his plot to bring Fallcrest low. He tells them that the Prince has made his home in the tower, and that he is currently entertaining a 'foreign dignitary' and his bodyguards. From the description, Shava recognizes the visitor as a mind flayer. Having gotten the information they wanted from him, Kraygin immediately beheads Kalder, to Chance's utter horror.
The party re-enters the laboratory to find the smoke-creature gone; what's more, Baris is also gone, a trail of bloody footprints leading further into the manor. The party follows them, but eventually they stop, and Baris is nowhere to be seen. They continue and eventually find stairs leading up. After a quick search of the second floor of Vashtarborg, the party finds the door to the tower; when they open it, they feel a distinct chill and the air is sucked into the stairwell they face. They ascend.
At the top is a small antechamber with a set of double doors; beside the doors is a plaque reading 'Chapel'. They enter the chapel to find half of the room gone, replaced with a shadowy landscape that shouldn't be there; Sredni and Silus recognize it as a Shadowfell breach. In the center of the room is an orb of pulsating darkness; they recognize this as a Gloaming Gem. In front of the gem is a large creature shrouded in shadow, and in front of it are four creatures very similar to Chance, though their expressions are completely vacant. Beyond them are two figures conversing, one of them flanked by two more creatures.
The enemies move to attack, and the party is quickly overwhelmed by the large spirit's aura of cold. The mind flayer moves forward and uses its psychic power to blast the party, turning invisible to those it affects. The other figure–the Prince of Dusk–turns invisible, after which Chance feels a presence in his mind; this presence surprises him later by making him attack Silus. Things seem bleak, but Silus manages to turn the tables by using magical teleportation to reach the Gloaming Gem, which allows him to take control of the spirit and use it against their enemies. Once this happens, the battle moves in their favor; the warforged fall quickly, and the mind flayer is soon swallowed up by the Shadowfell breach. The Prince tries to get Silus away from the gem, but everyone converges on him quickly, and he does not survive the onslaught for long. Silus uses the gem to close the Shadowfell breach, bringing Vashtarborg back to normal.
Their side of the bargain fulfilled, the party finds that the medusa has lived up to her side and departed quietly. The party brings Isolde and the others back to Fallcrest, where they are hailed as heroes. But who is this mysterious individual that has information for Chance? And what was the Prince of Dusk trying to accomplish? And who was the mind flayer meeting with him? And where is Baris? And who is Judgment? So many questions, left unanswered.