A devilish warrior. And a killer. Captured on a hellish world after attacking a military campsite and now imprisoned in a state-of-the-art cell inside one of the military’s top bases--Lazris.And Lana has been assigned to "study" him. To learn his secrets and gain his trust, if he is ever allowed to set foot out of his cell. As a top behaviorist, it is the biggest hurdle of her career.Asset X--or Xerus as he is called--won't give up his secrets easily. He is difficult, elusive, and--dare she say--unfathomably alluring...despite his seething demeanor and hard, frightening physique.Something subconsciously draws her to him. Something wildly irresistible. Even if his wicked smile and needful gaze could just be a ploy to win her trust and escape his cell.She shouldn't think of him like that. He is an alien after all. And possibly their enemy.For Xerus claims he is on a mission. A mission to destroy. And he cannot afford to fail. If he dares let Lana get close, dares open his cold heart to her, she could compromise everything.Heart's Prisoner is a complete standalone novel in the Dark World Mates series, a universe teeming with ferocious aliens and brave heroines. This book contains dark tones, heated intimate scenes, and intense moments with possible triggers including violence, and is intended for mature readers.