Angel's Body - Angel Series, #4

One body, two souls ... Helena is possessed by a demon, and those who matter most to her are blind to her plight. She's trapped in a body that she no longer controls, her soul in a constant state of torture. Desperate to be take back what is hers, Helena tries time and again to overcome the deranged demonic spirit that is using her body to wreak havoc in the mortal world. The demon, furious at Helena's attempts to thwart it and regain control, seeks an exorcist to cast her out.
The time has come for Helena to take a final stand and fight for her freedom. Only one of them can survive, but which one?