Torn between an intense infatuation with the mysterious woman who's been following him and a genuine affection for his imaginary high school sweetheart, things are already going downhill for Jonathon Derrick. But when the mystery woman's ex-boyfriend is found dead, the latest victim of a brutal murderer, Jonathon's situation gets much worse. Now he must somehow unlock the past secrets of a psychotic stalker and a jealous figment of his own imagination before he is mistakenly identified as a serial killer.
No specifics here to hook us. I love "genuine affection for his imaginary his sweetheart" though, so I have hope you can revitalize this.
Use the hook formula I've posted elsewhere #239l). Then garnish as needed.