On their way to report back to Inquisitor Sand after successfully receiving two important tomes from the possession of Deathwatch Kill-team Kronos, Acolyte Cell: C2’s ship is diverted by special order from the Office of Lord Caidin to investigate one of the Inquisition’s infamous Blackships, the “Validus”, which has been out of communication for several weeks and is a month overdue from its psyker tithing voyage. The Acolytes’ orders are to travel to the last known location of the “Validus”, locate the ship, assess the situation and recover the ship if possible.

Under the command of Captain Hedrak, the Imperial Navy Cobra-class escort ship, the “Storm’s Hammer,” makes haste to the “Validus’” last coordinates and upon arrival are greeted by a sight nearly unheard of- the “Validus” is floating stationary in the churning warp but it is surrounded by an unexplained area of unnatural calm warp-space. After assessing the situation, and taking into account the Blackships’ classified nature, the Acolytes decide to investigate the ship alone, leaving the “Storm’s Hammer” nearby to provide support if necessary.

They board the “Validus” using the “Storm’s Hammer’s” teleporter (which it is lucky to have from its throwback days as a personal escort for one of the Calixis Sector’s past admirals) and find the “Validus” to be a mix between a tomb ship and a house of horrors. Throughout the decks, the Acolytes find the ship’s crew either dead or in a state of unexplained catatonia. In addition,strange phenomena, such as weeping bulkheads, spirit forms, and frozen time anomalies, are observed throughout the ship. The strangest, and most persistent, of all of these unexplained phenomena is the strange voice(s) that can always be heard in the Acolytes’ mind; the only one that does not seem to hear the voice is the Untouchable, Quint, which hints to the fact that the Voice is psychic in nature.

Gathering information from the “Validus’” bridge records, as well as from a survivor named Hydra, who was a member of the personal retinue of the Inquisitor in charge of the “Validus,” the learn that the “Validus” received a strange transmission in the warp that lead it to the strange area of calm warp-space. While investigating this anomaly, the “Validus” was attacked by a strange psychic force which caused many of the crew and their human cargo to go mad. Many of the psykers broke free from containment and the ship was plunged into chaos as the Inquisitor and what able-bodied crew remained attempted to stop the rampant psykers. Strangely, several of the most powerful psykers sought each other out and joined together into a rare entity called an Amalgam, a rare occurrence (documented to happen perhaps once every 4000 years) in which powerful psykers join together into a group mind, or a hive mind, and together they are very powerful and very difficult to neutralize. The “Validus’” Inquisitor made a desperate failed attempt to vanquish the Amalgam, which was residing deep in the psyker cellblocks, and afterward the few remaining members of the Inquisitor’s henchmen could do nothing but contain the Amalgam until help arrived.

The Acolytes decide that they must stop the Amalgam and enter into the psyker cellblocks. Inside, they are confronted by all manner of horrors. Spirits appear from everywhere and attack their minds and the Acolytes physical bodies must staved off the attacks from mobs of mindless animated crewmembers that are intent on killing them. A couple of well-placed bilge grenades from Quint reduces several of the mindless crew members to festering pieces and the rest of the Acolytes are able to dispatch the last of the possessed crew. The spirits are banished thanks to Quint as his Untouchable aura proves to hinder their ability to maintain form.

Deep in the center of Cell Block 7, before the entrance to the furnace room, the Acolytes pass by the mass bodies of what appears to be the Inquisitor’s failed attempt to destroy the Amalgam. Once inside the furnace, the Acolytes come face-to-face with the Amalgam- a horror made up of a hundred psykers moving and speaking as one. The scene is too much for Quint, Rasar and Xerxes and they bolt from the furnace room away from the Amalgam. Red is too shaken to run and can only stand in place vomiting his guts out as his fear makes him lose his last meal. Only the Tech-Priest Vern is resolute and engages the Amalgam in a conversation.

Though difficult to fully understand, Vern learns that the Amalgam is actually trying to get a message to the Inquisition about a danger on the planet of Reth- a danger that will cost millions of lives if left unchecked. The nature of the danger is not specified and suddenly the Amalgam starts to break apart with devastating effect as it becomes unstable and its hosts start unleashing their psychic powers in uncontrolled fury.

With the barrage of unchecked psychic energy being unleashed on the ship, the Acolytes quickly decide that they need to leave before the ship breaks apart. Calling back to Captain Hedrak, the Acolytes are able to teleport themselves and Hydra off the ship just in time before the “Validus” explodes. Of what danger lies on Reth and of who or what sent the Amalgam remains to be seen…

• GM’s Note: This mission was written by the GM and inspired by the short story, “The Voice”, by James Swallow, which can be found in the Horus Heresy “Tales of Heresy” book.