Attilius leads his engineering crew on a pre-dawn investigation of the failing Augusta aqueduct but finds no water.

Corelia brings Attilius to her father's mansion to investigate dying fish, but the slave Hipponax has already been executed.

Attilius shuts the sluice gates to cut the navy's water supply and visits Admiral Pliny to request a ship.

Pliny agrees to outfit Attilius with a ship and crew and imposes water rationing across Misenum.

Attilius and his crew sail the Minerva to Pompeii, where the water supply is still flowing.

Attilius forces his way into a meeting with Pompeii's magistrates and secures supplies from Ampliatus for the repair mission.

Attilius divides his crew into teams and leads them out of Pompeii toward Mount Vesuvius to find the blockage.

Attilius locates the fault beneath Mount Vesuvius and lowers himself alone into the narrow aqueduct tunnel.

Attilius stays alone in the tunnel to remove the blockage and is nearly drowned when the dam collapses.

Pliny discovers a large cache of silver coins hidden in the black mud of Misenum's drained reservoir.

The aqueduct repairs are completed and water begins flowing again to the towns across the Bay of Naples.

Mount Vesuvius erupts and the peak of the mountain is replaced by a boiling column of rock and ash.

Pliny orders the entire naval fleet into the bay to document the eruption and rescue survivors from the shoreline.

Attilius finds Corelia in Pompeii and hides with her inside the reservoir as the volcanic surge destroys the city.

A legend spreads among survivors of a man and woman who emerged from underground after the eruption, soaked in water.

Attilius arrives in the Bay of Naples tasked with repairing the failing Augusta aqueduct, which threatens the water supply of two hundred thousand people. After gaining the backing of Admiral Pliny, he sails to Pompeii and uncovers a web of corruption tied to the wealthy and ruthless Ampliatus. Attilius leads a dangerous repair expedition beneath Mount Vesuvius, nearly drowning in the process, while Pliny discovers stolen silver coins in the drained Misenum reservoir. Just as the water is restored, Vesuvius erupts in a catastrophic explosion that obliterates Pompeii. Pliny sets sail to document the event and rescue survivors, while Attilius races back into the dying city to find Corelia. The story ends with the city buried under ash and a legend of two survivors who emerged from the earth.

Attilius's mission to save the aqueduct and survive Vesuvius.

Ampliatus orders his slave Hipponax thrown to moray eels as punishment for allegedly poisoning his valuable red mullet.

Attilius searches Exomnius's abandoned room at the aqueduct and finds a gold plate revealing him as a freed slave.

Attilius finds Atia badly beaten and abandoned outside Ampliatus's mansion and carries her into the city.

Pliny demonstrates the earth's subtle tremors to his officers by placing a cup of wine on the ground.

On the voyage to Pompeii, the crew discuss how Ampliatus bought up ruined property after the earthquake and sold it for enormous profit.

A mild earthquake rattles Pompeii as Attilius walks through the city; locals barely pause, explaining tremors are now common.

Attilius visits the brothel where Exomnius rented rooms and learns from the prostitute Zmyrina that Exomnius was hiding money.

Attilius meets the former gladiator Brebix, who introduces himself as the leader of the rough crew Ampliatus has provided.

Corax disappears from the repair site rather than ride back to notify Attilius that the fault has been found.

Pliny is woken by his sister and rushes to observe the massive plume of black smoke rising from Vesuvius.

The Minerva is grounded by falling pumice and the survivors take shelter at Pomponianus's coastal villa.

Pliny proposes a toast inside Pomponianus's villa while pumice stones crash onto the roof above the gathered guests.

Attilius evacuates Pomponianus's villa just before its roof collapses under the accumulating weight of pumice stones.

The group flees to the beach, where Attilius discovers from Popidius that Corelia was left behind in Pompeii.

Ampliatus is struck down and killed the instant the volcanic surge sweeps through Pompeii.

The events behind the main plot begin with Ampliatus's public cruelty and Attilius piecing together clues about his vanished predecessor Exomnius. On the voyage to Pompeii, the crew's gossip about Ampliatus's shady property dealings and a casual earthquake in the city underscore the fragility of the world Attilius is trying to save. As the repair mission unfolds, Attilius meets a dangerous work crew, Corax goes missing, and Ampliatus secretly moves to have him killed. When the eruption begins, Pliny races to observe it while Attilius's group is forced ashore by falling pumice and takes shelter at a friend's coastal villa. The evening's forced calm collapses when the villa's roof gives way and the survivors flee to the beach, where Attilius learns Corelia was abandoned. Ampliatus himself stays in Pompeii to the last, refusing to flee, and is killed the instant the volcanic surge strikes.

The secondary scenes behind Pompeii's corruption and unfolding disaster.

Attilius tastes the water at Ampliatus's mansion and confirms that sulfur in the pipes killed the fish, not the slave.

Attilius maps the failing aqueduct and calculates that roughly two hundred thousand people across the bay face a water crisis.

Tiro the blind slave nervously reveals to Attilius that he saw the missing engineer Exomnius in Pompeii just two weeks earlier.

Corelia pulls Attilius aside in Popidius's garden and warns him that her father is planning to trap him.

Ampliatus offers Attilius a share of the bath profits as a bribe; Attilius refuses and suspects Ampliatus is paying no water taxes.

Ampliatus receives a secret message at his feast and makes a deal with Corax to have Attilius killed during the repair mission.

Corelia steals her father's incriminating documents from his private office and escapes Pompeii on horseback toward Mount Vesuvius.

After surviving the tunnel flooding, Attilius surfaces and suspects Brebix deliberately let go of his safety rope.

Corelia arrives at the repair campsite and delivers her father's stolen documents to Attilius.

Attilius reads the documents and deduces that Exomnius accepted bribes from Ampliatus and feared an imminent volcanic catastrophe near Pompeii.

Corelia rides back to Pompeii and throws her father's stolen documents across the room where the magistrates are assembled.

Ampliatus locks Corelia in her room after she accuses him of being a thief and murderer before the magistrates.

Attilius climbs Mount Vesuvius alone and discovers the body of the missing engineer Exomnius, dead with no visible wounds.

Corax tracks Attilius on Mount Vesuvius and attacks him with a knife but collapses and dies from the volcanic fumes.

Pliny sends his slaves away with his notes, turns to face the advancing volcanic storm on the beach, and dies.

The novel's turning points begin with Attilius proving the innocence of an executed slave, setting him on a collision course with the corrupt Ampliatus. As Attilius investigates, clues about the missing engineer Exomnius multiply while Ampliatus quietly arranges his assassination through the treacherous Corax. Corelia defies her father by stealing the documents that expose his bribes, delivering them to Attilius at the repair site after he narrowly escapes drowning in the aqueduct tunnel. Together, Attilius and Pliny piece together the full extent of the corruption, even as Corelia's brave act of rebellion leads to her imprisonment by her father. Attilius's solo climb of Vesuvius delivers the final revelation: Exomnius's corpse and Corax's death by volcanic fumes confirm the danger that has been building all along. As the eruption peaks, Pliny accepts his death with stoic calm on the beach while Attilius makes his final desperate push into Pompeii.