the Dolphins of Laurentum is the 5th book in the Roman Mysteries series. After the volcanic eruption at Pompeii, Flavia's family are banktrupt. When in Laurentum with Pliny the Younger, wanting to find out about his uncle's last hours, he mentions a shipwreck that is visible and said to have been carrying a cargo of gold. Unfortunately, it is to deep for any of the local fishermen to reach it. Lupus (who this story is manly featered on, and tells about his past and what caused his muteness) reveals he is Greek, and is very good at diving. On his very first dive, he reaches the wreck, a feat no one else has been able to do, although Lupus considers himself out of practise. However the situation becomes dangerous when the hated slave trader, who sold Nubia, turns up. It is revelaed that he is Lupus's uncle, and he was the one who cut of Lupus's tongue.