The graveyard of the Hesperides - Lindsey Davis

Life is sweet for Flavia Albia and her soon-to-be husband Faustus. But
his new job as a building contractor runs into a problem: At the Garden
of the Hesperides a barmaid went missing years before; now the workmen
start unearthing her bones.

Albia takes on the task of finding out
what happened. Five more skeletons are discovered. Despite the fact that
nobody seems to know or care who died, violent attempts are made to
stop her enquiries.

Soon Albia is exploring the world of Roman
streetlife, where bars are brothels, workers lead brutal lives,
foreigners are muscling in on the gambling syndicates, and extortion is
commonplace. What's more there's little time to solve the mystery before
the wedding day when Albia is expected to show Rome that her affair
with Manlius is a much more than a casual fling. The gods, however, have
other ideas...