The Turquoise Sun — Linda Sandifer

SOMEWHERE IN TIME...
19th-century archaeologist Tanya Darrow is excavating the primeval cliff dwellings of the long-vanished Anasazi tribe -- and uncovers an expedition led by rival archaeologist and notorious playboy Keane Trevalyan. Determined to resist her handsome adversary, Tanya never dreams that Keane will become so tempting -- with time....

Lured into a subterranean cave, Tanya and Keane make the discovery of a lifetime: a mystical gemstone known as the Turquoise Sun. But the cave is also a passageway... to the 13th century! Lost in time -- and worshipped as gods by the ancient Anasazi -- Tanya and Keane are trapped in an eternal battle of love and war....

Against the untamed splendor of the primitive past, Tanya is drawn into a passionate liaison with the one man she dares not trust... a man who is rapidly sweeping her to a rapturous and perilous point of not return....