Miles, a 23-year-old guy, falls under an obsession with a girl and stalks her until she finally comes into his life. His game is soon set to start and she falls in love with him and discovers a grim truth; he's not like she thought him to be. 

Later on, however, she finds herself lost in the comfort of his undeniable truth, and the obsession is reverted to her, as he no longer wants to be part of the game.

"Till death do us apart," he said, though now I knew without him, I'd be better off dead.

Revertible Obsession