Season of Ghosts: The Missing Piece

The War for Crow's Foot began with a murder. Or a suspected one, at least.
Lyssa, long-time second-in-command of the Crows rose to claim leadership after Roric disappeared. He was dead - everyone knew that he was dead - but nobody knew how. In the middle of the district there was a Roric-sized hole and while Lyssa thought she should fill it, many in the organization weren't so sure. Which caused the internal strife. Which gave ground to the Lampblacks to finally challenge their long rivals and eventually make the push towards overthrowing the Crows.
All because of a little murder. A murder that was a mystery. Until now.
A great spectral scream has ripped throughout Doskvol. Whispers, ghosts and demons have all heard its call. Fragments and echoes of the last few hours of Roric's life as he was betrayed and finally murdered by Lyssa. Many take this as proof that Roric's ghost is still out there, and with that possibility present the hunt is on. Many would give great sums to possess the knowledge of that spirit.
One of those persons is the demon Bale, who approaches the crew to bring back Roric's spirit in a containing vessel. A collector of stories and intrigues, he wants to know the old man turned new ghost's secrets. The crew tracks the spirit of one of the Crows who was betrayed along with Roric, an infamous cutter by the name of Gustav. The Bloody Crow of Crow's Foot. Known for his viciousness, he disappeared along with Roric. The only one who knows anything about where they may have gone is Gustav's sister, Maria, who points them in the direction of Ulst Manor, a house impaled by one of the great lightning towers of Doskvol.

Once upon a time there used to be another district in Doskvol. But one day the Deathlands rolled in a stronger tide than ever before and swallowed it whole, pulling every spirit and person back into the great black with them. It was the beginning of the end for Doskvol, but it coincided with the creation of the lightning wall. Some say coincidence but others say plan. Regardless, the wall went up and one of the towers, those great black spires that are the half-magic, half-mechanic products of the Sparkwright's Guild, was placed in the middle of the Ulst Manor, a blocks-spanning estate right on the river's edge of the Lost District and what's become Six Towers.
Many go into the Lost District and the Deathlands beyond looking for lost treasure. Things abandoned and forgotten when the walls fell. Many of those people never return. Lyssa promised Roric an easy score just inside the lightning wall. A secret stash. An embarrassment of riches. And there, far from anywhere, she murdered the man and his compatriots. She left the bodies. She'd heard about the particular effect of the Ulst house, how the reason that it had never been looted was because the looters who had tried and died remained there, their spirits trapped inside the mansion as if in a little Doskvol of their own, the lightning tower piercing the mansion's middle creating a ghost trap nothing could leave and nothing could enter.
The crew cross to the edge of Doskvol and bind the spirits they find their after much struggle. Aldo is momentarily possessed as two of Roric's fellow spirits force themselves into his bones. Deeply shaken by the encounter, he attempts to make sense of what to do next after they deliver the spirit of Roric to Bale.