I'm using The Black Sepulchre, the first adventure in The Apostasy Gambit campaign published for Dark Heresy, but for the system we're using my own hack that combines Dark Heresy with Savage Worlds. It worked well; the characters felt competent like the agents in Abnett's fiction, so that is a win.
Below is a record of what went down.
The Characters
Ash Underblade, assassin plucked from a Schola Progenium and trained for murder
Sister Rhiannyan, member of the Sisters Repentia who seeks atonement for the galaxy's many sins
Absalom Athanasius, sanctioned Imperial psyker with a talent for telekinesis
Erastus van Saar, ancient and venerable savant who hails from a Hive World of scum and villainy
Events
The retinue had been tasked by Inquistor Sebaton Valker with collecting evidence of Bulagor Thrungg's heresies; in particular, they were to locate any items from the "Museum of Apostasy" in the dissolute noble's manor. To fulfill the Emperor's will, the retinue found themselves in a Valkyrie swooping in on Thrungg's manor as the Imperial Guard stormed his compound and engaged Thrungg's household guards in combat. The Valkyrie shot a hole in the glass-ceilinged chapel so that the retinue, each of them strapped into a grav-chute, could infiltrate the manor.
The chapel was supposed to be unoccupied, but instead two of Thrungg's guards and a gun servitor had been pushed back to the chapel. A pitched battle ensued, but the retinue managed to kill one of the household guards and disable the gun servitor. The other guard surrendered, but Sister Rhiannyan decapitated him with her Eviscerator anyway. Those who deny the Emperor must fall!
With the room clear of threats, they investigated the chapel. The most noteworthy thing in the room was a dead priest, whose arm had been severed at the elbow, but his lower arm was missing. He was lying facedown in a pool of blood; there was also a great quantity of black feathers that had been scattered throughout the blood. In the priest's remaining hand was a book of Imperial prayers--but Erastus quickly determined that the sermons contained therein had been altered in such a way as to encourage a congregation to adopt heretical views.
Their vox beads crackled with a message from Captain Scipio of the Imperial Guard; Bulagor Thrungg had slipped away and was holed up in the manor's menagerie. He asked the retinue to cut off Thrungg's escape. They opened the hallway door and were nearly felled by a blast of fire--the las fire from the guardsmen and the household guards had lit the manor on fire.
In the menagerie, hundreds of exotic birds had been released from their cages and were flying everywhere, obscuring line of sight. When they finally spotted Thrungg he was holding the leashes of two vicious beasts that looked like hybrids of crocodiles and hyaenas. They also noticed that one of Thrungg's arms ended in a large, demonic, armor-plated hand. Thrungg loosed his creatures on the retinue. Sister Rhiannyan fended off Thrungg's beasts. Ash crept into the underbrush to get the drop on Thrungg. Erastus took potshots here and there. Absalom focused his will and used his telekinesis to pick up one of the creatures and hurl it at Thrungg. This proved to be highly effective--the creature bowled into Thrungg at velocity and broke the heretic's neck.
When Thrungg died, the demonic hand detached itself from his body. Ash tried to destroy the hand with gunfire, but it was impervious. The retinue decided to place the hand in a bird cage so they could carry it around without touching it directly. Also, in one of Thrungg's waistcoat pockets they found a key. The mystery of the key's purpose was solved when they found a maid cowering in fear in a side room. The maid informed them that the key unlocked the trapdoor leading to the Museum of Apostasy. She showed them where the trapdoor was--underneath the body of the dead priest in the chapel.
Down in the depths beyond the trapdoor, they found a series of pedestals showcasing a variety of heretical items. Among the weapons, Xenos artifacts, and books of Chaos was a single data-slate. When the data-slate was examined, it powered up of its own volition; it flashed a strange image of a golden cathedral atop a blackened heart. The data-slate also contained Thrungg's personal diary of heretical thoughts and his involvement with the Ruinous Powers of the Warp. Sister Rhiannyan recognized the cathedral as the Gilded Cathedral of Barsapine.
After the group forwarded the seized forbidden items and their findings to Sebaton Valker, he commanded them to board a rogue trader he had hired and make their way to Barsapine in search of information about the origins of the demonic hand that Thrungg had attached to his body.
The city of Kephistron Altis on Barsapine was located on the part of the planet that was cloaked in perpetual darkness. An orbital mirror had been placed to allow a single beam of sunlight to fall on the city. It was positioned to hit to Gilded Cathedral--the shining place of worship illuminated the entire city.
At the Gilded Cathedral, the retinue were greeted by the elderly Abbot Jurutas, who offered to show them to the library where they might find the information they sought. On the way to the library, Jurutas pointed out a large something built into the cathedral that was covered with an expanse of black velvet. Abbot Jurutas explained that it was the Black Sepulchre, a tomb that hid a great weapon of the Imperium. Once they were ensconced in the library, the retinue decided to split their efforts. Erastus would look through the books for any references connected to their previous mission, while the others would attempt to take a look inside the Black Sepulchre.
Sister Rhiannyan caused a distraction by flagellating herself with her scoriada. Meanwhile, Ash attempted to look under the velvet covering. What he saw was a black doorway with a protrusion that looked not unlike a lascannon. However, attempting to get close to it was made impossible due to the presence of a protective field that repulsed their advance.
Back in the library, Erastus found references to a Haematite Cathedral that was involved with the Hekate dynasty, the Changer of Ways, and a Warp entity called the Dei-Phage. He also found corrodinates for the Haematite Cathedral. After Erastus relayed his findings to the others over their vox channel, they decided to pile into their transport and head to Haematite Cathedral to gather more intel. However, they were attacked on the steps of the Gilded Cathedral by cultists pretending to be beggars. Among the cultists was a pyrokinetic psyker!
The cultists were dispatched fairly easily, but when Absalom attempted to channel his powers he triggered the Perils of the Warp--his eyelids melted, fusing his eyes closed! Luckily, Sebaton Valker had equipped them with a medicae servitor skull that was able to provide some (painful) impromptu surgery to unseal his eyes. These are the mortifications required of those who serve the Emperor's will.
Next time: The Haematite Cathedral.