Part 1

When the children's handsome Greek tutor Aristo gets a letter, he asks Captain Geminus for urgent passage to Corinth.

Flavia's father refuses, and the two argue. Later that night Flavia's father is stabbed and Aristo is seen crouched over the body.

When Aristo runs away, the friends and their bodyguard Caudex follow him. Only Nubia believes he is innocent. But if Aristo didn't do it, who did?

Part 2

Doctor Mordecai has left Jonathan to look after Flavia's father, who is gravely ill. As the others pursue Aristo, someone else seems to be after them.

Also, the sightings of Aristo are conflicting. Only Nubia still has faith in Aristo's innocence. Will she be proved right or gravely disappointed?

Meanwhile, back in Ostia, Jonathan must make a life or death decision.