This film follows two detectives, Charlotte and Frank, searching for a serial killer in December. Charlotte begins to suspect Frank is the killer due to evidence, but ignores it due to their friendship. On her birthday, Frank reveals he is the killer and was trying to impress Charlotte by killing women like her. A fight ensues and gunshots are fired, but it's unclear who shot whom. Frank and Charlotte met years ago when Frank counseled Charlotte, and Frank developed split personalities and feelings for Charlotte.