College junior Amy Clear is awakened before dawn by screams outside her dormitory. She joins many fellow students watching the aftermath of a murder, and is infatuated when the handsome young police detective arrives, with his fedora and cigarette and easy smile. Amy comforts the acquaintance who discovered the victim, and convinces the detective to let her be his helper. Amy gets one-on-one tutoring on securing a crime scene, collection of clues, and techniques for interviewing and interrogating people. Her careless intimacy with a prime suspect threatens to derail the investigation, until she and her dyad Paul are forced to defend themselves against an ambush. Paul hates police but decides detectives are more about solving a puzzle than making people behave. Along the way he meets Christine, a young woman who hears her own voices and therefore is comfortable with Paul -- she calls him Paulette -- and Amy sharing the same body. Christine helps Amy on a field trip to take forensics samples when the real killer makes their identity known. Can Amy and Paul and Christine save themselves? And will Amy pass the psych class she's been avoiding all semester?