Conan and the Amazon — John Maddox Roberts

Roaming the hills of Brythunia Conan comes face to face with a legend--Achilea, once Queen of a tribe of savage women, is a consummate warrior, as fierce as she is beautiful. Together they set out to uncover the riches of the long-lost Janagar, a mighty city that stood tall for five thousand years. It was abandoned by its people, who fled on one strange night, never to return. Treasure hunters beware! Deadly horrors are waiting for Conan and Achilea deep in the bowels of Janagar