I've Got You Under My Skin

The first rule of demonic possession: Don't fall in love
Lacy Gordon, amateur paranormal investigator, is experiencing the supernatural world in a way she never expected. While climbing out the window of a haunted house, an unseen force collides with her, thrusting her into the unknown. She soon finds herself trapped in the depths of her own mind, desperately screaming for freedom. To her surprise, someone responds.
This disembodied voice belongs to Tonkitgrol, or "Kit," as he prefers to be called—a demon with somewhat of a heart. Even so, Lacy isn't about to relinquish control of her body. Armed with relentless curiosity, she bombards him with questions, hoping to annoy him into leaving her be. As she delves deeper into the mystical realm, she uncovers more about Kit's tormented past. Once human like her, he endured centuries of suffering in Hell before choosing to become a demon.
Despite their differences, Lacy and Kit forge an unlikely partnership. Together, they work on a submission for a paranormal investigation reality show contest that Lacy plans to win. As Lacy finds her feelings for Kit inexplicably deepening, she faces an agonizing decision: should she exorcise him and shatter her heart, or dive into the chaos of sharing her life—and her body—with a demon straight from Hell?