Pompeii is a 2003 historical fiction novel by British author Robert Harris. The novel blends together the history of the eruption of Mount Vesuvius in 79 AD with a fictional plot about an engineer sent from Rome to repair the city’s aqueducts.

This study guide uses an eBook version of the 2003 Ballantine Books edition.

Plot Summary

Marcus Attilius Primus is a young aqueduct engineer, also known as an “aquarius.” His father and his grandfather were both engineers; they were famous for working on Rome's massive aqueduct structures. Attilius is a widower who lost his wife in childbirth. He is dispatched south from Rome to the Bay of Naples to replace the former engineer Exomnius, who has disappeared in mysterious circumstances.

At the beginning of the novel, Attilius leads a team of disgruntled engineers on a pre-dawn investigation into the source of a potential leak in the local aqueduct. The August aqueduct provides water to many of the neighboring towns, including Pompeii, Misenum, and others. Attilius is aware that the most senior member of the crew, Corax, dislikes him. Attilius ignores Corax's scathing comments and locates an underground spring. The men evacuate the spring, but the local water pressure is so low that it cannot be used.

In the town of Misenum, a former slave turned rich merchant named Ampliatus has a large mansion. His mansion includes a number of beachside fisheries. In one of these fisheries, he keeps red mullet. These fish are very valuable and, when they die, Ampliatus orders that the slave in charge of feeding the fish must be executed. He wants the slave to be thrown to his moray eels. Ampliatus's daughter, Corelia, does not believe the slave is at fault. She runs to the aqueduct in Misenum to find Attilius in the hope that he can prove the slave's innocence. Attilius reluctantly agrees to follow her to her father's mansion, where he discovers that the local water supply is infused with sulfur. The sulfur, rather than the slave, killed the fish. However, the slave has already been executed.

After a brief investigation, Attilius decides that the problem with the lack of water in the aqueduct can be traced to the town of Pompeii near Mount Vesuvius. Pompeii's water supply continues to function while the water to the surrounding towns is cut off. Attilius visits the admiral in charge of the naval fleet to ask for help. The admiral is the famous writer Pliny the Elder, who has written many volumes of an encyclopedia. Pliny agrees that the water supply needs to be safeguarded. He outfits Attilius with a ship and a team and tells him to investigate the blockage.

Attilius and his men travel to Pompeii. Ampliatus is already in the city. He has a longstanding interest in Pompeii, having invested heavily in property in the wake of an earthquake many years before. The real estate speculation made Ampliatus's fortune. Now, he is constructing public baths in the city, so ensuring that the water supply is maintained is important to him. He hints at his willingness to bribe the local water supplier, raising Attilius's suspicion that Ampliatus is not paying his water taxes. However, he accepts Ampliatus's offer of men and supplies as the surrounding cities cannot last long without water. Ampliatus arranges to have Attilius assassinated, making a deal with Corax who is all too happy to kill his despised boss. Attilius suspects that Ampliatus is engaged in widespread criminal activity.

Ampliatus’s criminality is confirmed when Pliny the Elder contacts Attilius, informing him that a large number of Roman coins have been discovered dumped at the bottom of Pompeii’s reservoir—money that was supposed to have been sent back to Rome. Attilius deduces that Exomnius planned to retrieve the coins once Ampliatus’s water scheme had drained the reservoir sufficiently. Corelia helps Attilius find evidence of her father’s criminal activities. Attilius begins repairing a tunnel under Mount Vesuvius, finding evidence in Exomnius’s records that his predecessor was worried about the phenomenon surrounding the volcano because of his own experience when Mount Etna erupted near his hometown.

Noting Attilius's unwillingness to take a bribe, Ampliatus hatches a plot. He arranges for Corax to kill Exomnius, whose corruption is revealed when Pliny finds a treasure trove of silver coins in the rapidly-draining reservoir in Misenum. Attilius leads his expedition out of the city. Corax vanishes but the team find the issue. They work hard to unblock the pipe, though Attilius is nearly drowned in the water pipe. In Pompeii, Corelia defies her hated father and steals documents proving his corruption. She leaves the city, bringing these documents to Attilius.

As the water supply is fixed, Mount Vesuvius begins to erupt. Attilius sends Corelia back to her father's house and his men back to Pompeii. In the meantime, he travels to Mount Vesuvius to investigate the eruption. There, he finds Exomnius's dead body. Corax tracks Attilius and tries to kill him but dies due to the poisonous fumes as the volcano begins to erupt. Attilius wants to go to Pompeii to save Corelia, as the city is in the path of the erupting volcano. He is diverted back to Misenum, where he reconvenes with Pliny. They set sail into the bay on a rescue mission. The boat is forced to land when pumice stone begins to fall from the sky. Pliny documents everything. Attilius leaves to find Corelia, and Pliny accepts his fate, dying on the shoreline.

Attilius finds Corelia in Pompeii. He helps her escape from her father as the volcano eruption intensifies. They hide together in the reservoir in Pompeii as smoke, gas, and rock fall from the sky. The explosion of the volcano kills everyone in the city, including Ampliatus. The city itself is buried under ash and debris. According to a local legend, however, a man and a woman managed to survive the explosion. They were spotted exiting the tunnel days after the explosion, though many assume that this story is just local superstition.