From the publisher:

An exciting space opera of blockbuster proportions from the creators of Warship Jolly Roger and On Mars!

After an interplanetary religious war that devastated the galaxy 200 years earlier, four gods nicknamed the “Great Quartet" decided to build a new empire. They established a violent and repressive dictatorship, annihilating all forms of religion other than that devoted to their own worship. The Divine Legions were created to enforce this order, but despite their surveillance, different species of aliens continued to secretly worship their ancient gods. This situation gave rise to a galactic market in alien relics linked to many now-banned religions. That means smuggling and the birth of Relic Hunters. Aspiring up-and-comer Xia, a human, and Little Mercur, a masked alien of unknown origin, are among the best relic hunters in the galaxy, and they're joined for a new mission by Vitellius, a former centurion who deserted the Divine Legions.