The elevator slowed to a halt hundreds of feet up the tower spire. Seemingly trapped, Mormeros woke up Cyrus Belview and began menacing him. The frightened servant revealed a hidden ceiling tile and admitted to tricking the party to lure them away from the catacombs. They ascended the elevator's trapdoor to a landing between spiral staircases, underneath an ancient Portrait of Strahd in crimson armor. Ajuni lifted a conspicuous rug and was immediately restrained as it animated, alongside the Guardian Portrait. As Ghalwin beat the Rug of Smothering into his bag, the fake Strahd began casting real spells.
Though they were hypnotized and Ghalwin was smothered in turn, Mormeros was eventually able to dispel the magical effect on the portrait. He and Ezmerelda then destroyed the painting as Ajuni and Tobias slashed the rug off of Ghalwin; under further threats, Cyrus ran off, promising to keep quiet about their misadventure. Though they heard a heartbeat not far away, they chose to follow the sound of violin to the guest lounge, where Escher was playing.
The beautiful vampire was flirty, jealous, and depressed, and they learned from him that the castle contained a "brazier room" above the dungeons that allowed for fast travel. He made up with Ajuni, who explained her position on Strahd, and was quite coquettish towards Ghalwin, though eventually turned down the paladin's advances. However, after many strange lies and status plays, he became irate at Mormeros. The tiefling requested that Strahd's groom fetch him a "nightcap", and in turn, Escher made Mormeros cup his hand and swallow his own blood, as well as much of his pride.
In a huff, the vampire spawn left them to their rooms, where Tobias rummaged about and found another trapdoor leading up from their closet. Beyond a bedroom filled with foul alchemical ingredients, he heard Anastrasya's laughter. He, Ghalwin, Ajuni, and Ezmerelda made to sneak past her door into the hallway, leaving Mormeros invisible to charm her. On their way out, however, they let out three black cats, who began pawing at their mistress' door. Ajuni and Ez quickly turned the rest invisible; they opened the door ahead of them but remained still, and a manic Anastrasya ran past them, chasing their shadows.
They found that she had been gutting corpses and turning them into potions of healing, and Ghalwin began filling his spare vials with the people-juice. They went to leave, but Momo was noticed by the cats, and realizing they had little time to investigate the tremors, the invisible party followed him up and out to the drum roof of the castle. A rain-soaked Anastrasya awaited him atop the windy rooftop, and Mormeros had a sexually-charged encounter with Strahd's bride. Stunned by female attention, he accepted her blatant advances, but as she removed her dress and put her fangs into his neck, the warlock rebuked her with devilfire.
On instinct, Ajuni blasted Anastrasya away from him, and the bride misty stepped then spider-crawled away alongside the tower. Realizing that he couldn't let her escape, Mormeros shouted after her but fumbled his words. Ten-Zras noticed this opportunity, and contacted Mormeros again; rather than suggesting that it was "normal for a tiefling to explode", Mormeros this time requested the full help of the Kingmaker. He breached his contract with Dharus and fully committed to the Dark Power, and in turn, he was choked out by black shadow. He again faced death, but again, Ajuni was there to heal him.
Ten-Zras temporarily took over Mormeros, and with mass suggestion, commanded all who heard him to kneel. Though Tobias and Ghalwin resisted, he demanded that Anastrasya not tell Strahd, then gave his "greetings" to the rest of the party, claiming to be different than Yyrga and Delban. Mormeros returned to consciousness bearing a permanent ghostly crown, and now possessed dread power even stronger than Ajuni's. Not wanting to think too hard about the implications of this, Ghalwin healed him and led the group across a blustery stone bridge, where they pulled a hidden door and found a massive heart suspended in the north tower's shaft.
Tobias deduced that the Heart of Sorrow was a crystalline construct, embedded with magical roots and fueled by the power of a Gemstone of Life Growth. They had to destroy the crystal to remove the stone, but halberds along the staircase's walls would animate if it was threatened. They decided to step back onto the bridge, then inundated the spire with fireballs, lightning bolts, and arrows. Their maelstrom of evocation exploded the heart and destroyed the Flying Weapons in a single assault, and the now-extremely-confident Mormeros caught the grey gemstone with a deft mage hand.
This destruction was met with shouts from a hundred feet below. The Heart of Sorrow had been destroyed, and vampire spawn at the base of the tower were looking to retaliate!