Ghosts Series by Cindy Miles

Knight Tristan de Barre and his men were murdered in 1292, their souls cursed to roam Dreadmoor Castle forever. Forensic archeologist Andi Monroe is excavating the site and studying the legend of a medieval knight who disappeared. But although she's usually rational, Andi could swear she's met the handsome knight's ghost. Until she finds a way to lift the curse, though, love doesn't stand a ghost of a chance.

A twelfth-century warrior-turned-Guardian Knight, Gawan of Conwyk is about to finally become mortal. But then he finds a beautiful woman by the side of the road near Castle Grimm-she is his soulmate, and it's up to him to save her life. Ellie doesn't remember who she is or how she got to the north of England. Together they set out to solve the mystery of her almostdeath, but neither Ellie nor Gawan is prepared for the soul-searing passion they discover...

Bestselling mystery novelist Amelia Landry journeys to the Scottish Highlands to stay in a remote 14th-century tower, hoping to re-awaken her imagination. She finds the inspiration she seeks in the ghostly form of Laird Ethan Munro, who has spent six centuries trying to discover why he is neither alive nor dead. Ethan senses that Amelia may be the one he has been waiting for. Only she can uncover the truth behind the curse and free his heart...