After almost a year of deliberations, the Consilium has decided to send a cabal to determine what danger the Antediluvian in the Underworld poses. The Chthonic Road has been picked for this mission due to their extensive knowledge about the Underworld and vampires in general. But they have received other orders as well. Heirophant Babbage has commanded the Mysterium members to find out if the vampire is a danger to the city, find its weaknesses or origin and get that information back to the order no matter the cost. Virgil however has his own orders. If the vampire is a danger to the city, he is supposed to seal it in the Underworld, even if he and his cabal are trapped there with it.
They prepare by first investigating their destination and the subject of their journey. The Ebon Cross's description of their encounters helps with much of their planning. What they can learn about the Antediluvian is limited to legends about the Black Hand, a secret society of vampires who believe that the Antediluvians, primordial vampires, will rise and usher an apocalypse. Supposedly the Black Hand had an item of great value stolen from them by a group known as the Circle. These other vampires also worship a being called the Antediluvian, possibly implying they stole the sleeping form of one. As for as their destination, the Empty Chapel might be a reflection of a Jesuit mission in the area that was destroyed in the 17th century. Additionally Lindenbrock gets the cabal's extensive map of the Underworld together.
Before leaving Big Sixteen heads down to the deepest levels of the Censorium, where the artifacts whisper in mad voices about lost secrets and hidden dooms. The voices are now focused on the subject of the coming danger. They seem to know that the Antediluvian is coming and welcome it. Seeking something useful for the journey, he comes across a mystic wood carving from the Pre-Columbian period. He ignores its cries for release and packs it into Virgil's bag.
The cabal's descent through the underground tunnels of Chicago is quick, disturbed only by the distant sounds of screaming and combat. Eventually they find patches of ash along their trail, remains of slain vampires. Virgil is able to conjure the last sight of the victim, a scene of horror as feral vampires, known as larva, ripped the creature apart to suck out its heart's blood. The mages are unsure what could motivate these usually simple creatures to such a level of ferocity.
Traveling in Twilight the rest of the way, they soon reach the gate to the Underworld. The cabal's chosen gate is a bare stretch of wall in an otherwise abandoned tunnel beneath the streets of Chicago. The bones of many animals and several homeless people litter the way. Something draws those about to die to this site. Even now there is the freshly decaying corpse of a cat lying there unmolested except for the maggots. Scratching a shard of ivory on the wall triggers the gate and leads them into the Underworld.
Quickly they descend through the tight earthen walls, lit only by softly glowing ghosts. The floor is moist, covered in small brackish puddles from the water dripping from above. As they go Virgil begins to hear whispers nearby, asking him to release it. Realizing it is the artifact he is carrying, he shoots a questioning look at Big Sixteen, who says the item will help them.
Further along they come across a ghost doing something odd. He seems to be writing on the wall in a crude attempt at High Speech. Suspecting he might know something, the cabal halts and tries to talk to him. Virgil recognizes him as William Holmes, a promising sleepwalker that the Guardians were watching. He supposedly died in an accident when a brick fell on his head. While Big Sixteen heals the ghost's mind, Dante distances himself from the others, recognizing his own handiwork. When questioned William is able to explain how he died and that he was close to grasping the truth. He becomes flusters as he realizes he had died before Awakening but Big Sixteen consoles him that he won't remember it, dismissing the spell. A look at the symbols points to him possibly Awakening as a Thyrsus. Before they leave Big Sixteen claims the ghost's final name.
Lindenbrock finds them a shortcut to the river but it involves a climb down a fifty foot chimney. She quickly maps out a path and gets down, waiting at the worm covered floor as the others slowly descend. Pressing on they soon smell the metallic scent of the River of Blood. It soon is visible stretching out before them, the banks obscured by reeds. A withered Native American in a canoe waits by the shore. They quickly bribe their way across the river. Dante gives him a picture of his wife, Lindenbrock a carabiner from the cave-in that Awakened her, Big Sixteen a shovel from his own Awakening, and Virgil gives him the keys to his motorcycle.
As they slowly cross the river, they see dozens of ghosts waiting on the other side. They are gathered in clusters, with some occasionally drinking from the river. A quick study reveals them to be former mages. Some are dressed in ceremonial robes, others suffering the wounds of occult horrors. The cabal is able to see many different Orders and Paths represented, including Seers of the Throne. They seem to be waiting for something.
They disembark and mingle with the ghosts. The dead seem fixated on the river of blood, often drinking from it. It looks like they hope to gain something from it but are always frustrated. Virgil is able to detect an artificial anchor to all of the ghosts. It seems to be located in the Underworld with them but if it was brought to the surface, these ghost mages would also escape. Virgil tries to break the bond with Death magic but fails spectacularly as Paradox inflicts a slight madness upon him.
As Virgil begins to unconsciously vocalize his inner thoughts, they find the ghost Dilios that the Ebon Cross encountered earlier. The Colonial era Arrow tells them about the destruction of the Dominion, the Empty Chapel. The Antediluvian is on the move and the ghost mages will follow it, addicted to its blood. He repeatedly warns them to leave.
Then Dante is suddenly attacked by the ghost of a young black woman. As they fed her off, she shouts that Dante stole her life just as she was Awakening. Virgil, still affected by the paradox, admits his guilt over his legacy's Left Handed practices.
As they try to take this in, they are suddenly confronted by the desiccated form of the Antedeluvian. Terrified by this horror and urged by her artifact to abandon her friends, Lindenbrock hurriedly leaves. The others soon join her by the river. The creature seems to barely pay them any attention, slowly drifting to the river's edge to lap at the blood.
They quickly pay the ferryman again with Lindenbrock and Big Sixteen trading their blood for passage in their haste. Virgil gives the old Indian a prized hip flask while Dante trades a picture of his children. As they sail away, they study the creature, reading in its aura a foreboding doom. It is a harbinger of sorts. It is also clearly an anchor to the ghost mages. Dante wonders aloud if it is possible that this is only the spirit of the Antedeluvian, and that its physical form may be in the city above them. Big Sixteen tries to see if the ghost of William is connect to this somehow using his Final Name. Unfortunately all he learns is that his cabalmate, Dante, caused the ghost's death.
As they reach the far shore, they see the Antedeluvian slowly drifting across the river toward them. They begin to race back to the surface while back at the river the ghost mages bargain with the ferryman.
Scrambling and climbing upward, they beat the vampire to the gate to the mundane world. They realize that there may be trouble on the other side, just as it opens and a horde of feral vampires attack. The monsters fight tooth and claw to get into the Underworld, while the mages try to get out. Thankfully the cabal is rendered invisible by some quick thinking by Big Sixteen. Virgil attacks using his pump action shotgun, while Lindenbrock stabs at them with little result. The giant Big Sixteen is swarmed by the creatures and knocked to the ground. One latches onto his leg, trying to gnaw through. But Virgil comes up from behind and dissolves it with a potent Death spell. Dante meanwhile hangs back and takes careful shots at the incoming blood suckers. Big Sixteen tries to free himself by turning his flash light into a flame thrower. In desperation, Virgil collapses the ceiling, crushing horde and himself. At the same time, Dante destroys the gate, sealing them in the Underworld. Amid the confusion, Lindenbrock finds herself on the other side, under Chicago. She runs to get help, expecting the others to head for the nearest gate.
Virgil slowly digs his way out with the others' help. As they dust themselves off, the Antedeluvian arrives. Initially it contents itself by draining the remaining vampires who have become docile in the presence of their master. Seeing the gateway closed it turns to the only beings nearby, the cabal. They distract it by throughing the now smoldering block relic from the Censorium. It bursts into fire elemental which bows before it. While it is distracted, they decide to strike first. Virgil attacks its corpus with the Death Arcanum while Big Sixteen sends it flying. As they flee, it lashes out with its mind, almost knocking Virgil senseless with a stream of horrific images. They flee across the Underworld pursued by the monster.
A few hours later, Lindenbrock arrives at the sanctum of the Ebon Cross. Banging on the door in the early hours of the night, she wakes up Colt. She quickly explains the situation and the Thyrsus arms himself and wakes Adele. Together the three of them head to the Underworld gateway in the backyard cemetery. Colt quickly calls Mammon, as Adele opens the doorway. Lindenbrock rushes in just as the rest of the Chthonic Road comes running out...