Marcus Attilius Primus is the young engineer and the protagonist of Pompeii. When he is sent south from Rome to the Bay of Naples, he does so heavily burdened by expectation and trauma. He is a widower, a man whose wife died tragically during the birth of their first child. As such, he finds himself suddenly alone. Even his mother and his sister remain in Rome, further isolating Attilius and leaving him alone with his dark thoughts.

Fortunately for Attilius, he loves his work enough for it to provide a suitable distraction. He is an aqueduct engineer, and he comes from a long line of similar professionals. His father and his grandfather both worked on the most famous aqueducts in the Roman Empire, so he feels a sense of responsibility to live up to the family reputation. This responsibility is tinged by his loss, however. Whenever he thinks about his ancestors, his mind naturally turns to the descendants that he has been denied. The death of his wife and child mean that he will be the last in the line of engineers. Therefore, he has a responsibility to acquit himself to the best of his abilities.