Under Lock And Key

Description for UNDER LOCK AND KEY by Sylvie Kurtz:

SHACKLED HEART

On a stormy Texas night, Tyler Blackwell awoke from a car crash to find himself in a castle dungeon, bound under lock and key by an ephemeral jailer with haunting eyes and virginal flesh that begged for a man's touch. Mysterious Melissa Carnes -- the woman Tyler had been sent undercover to defend from a deadly enemy intent on destroying her life -- was more tempting to Tyler than any assignment. And being her "prisoner" had its advantages. But could Tyler penetrate the cold stone wall Melissa had built around her heart before the past emerged like the grim reaper to sentence them both to life terms...?

Harlequin Intrigue #712, May 2003.