Lord Dragon's Conquest. Dragon Lords, #1

A rare discovery. A secret world. A lover beyond her dreams. Archaeologist Keltie Clarke makes the find of a lifetime inside a remote mountain cave. But her ambitions are challenged by a mysterious stranger who confronts her at the site. He tries to wipe her memory of the entire event-as if she could ever forget the handsome man. But nothing can shake her conviction that she's seen the impossible. Larkan is a Flameborn warrior trained to protect his shapeshifting dragon kin from the outside world.
He is also one of the privileged few allowed to venture beyond the dragons' mountain home. When the kind and lovely Keltie stumbles into his territory, she puts her safety and his freedom in jeopardy-not the least because her courage inspires him to defy his beautiful but deadly queen. That puts the lives of everyone-humans and dragons-at terrible risk. The stakes are high. Keltie has found a powerful secret that only a dragon can unlock.
Both she and Larkan must retreat to the lives they know-or leap together into peril and legend. Second edition. Previously published in 2014 by Harlequin Nocturne Cravings