William and Mattie were childhood sweethearts. Whenever William got into trouble, Mattie was there to protect him. They grew up together and, together, they were inseparable. Then...the car accident happened. Mattie died. When she came back as William's guardian angel, they were together again. But...it hasn't exactly been so heavenly. Every time William approaches a girl, Mattie "protects him," aka sabotages any attempt at romance. Now, William can't help but wonder if she is his guardian angel or a personal devil.