In Unforgettable Ray Liotta plays Dr. David Krane, a medical examiner investigating crime scenes for the Seattle Police. While investigating a drug store robbery and murder he discovers a clue that he believes is a direct connection to the unsolved identity of the person who killed his wife. Dr. Krane's wife was found murdered in their home, and the doctor was tried but not convicted, on the grounds that the Police mishandled evidence. Krane, a recovering alcoholic, is still obsessed with solving his wife's murder. Krane attends the lecture of Dr. Martha Briggs (Linda Fiorentino), who is studying the technique of memory transferal in rats that involves injecting spinal fluid from one animal to another. When Krane steals the serum and begins combining it with spinal fluid from recently murdered victims he is able to experience a host of sensations the primary one being the actual visual memory of the murderer in the cases. The major threat to the serum is that it puts tremendous pressure of the human sensory system and can lead to heart attacks in humans. When Dr. Briggs realizes that he has stolen his serum and is abusing it she is both fascinated but alarmed and tries to stop him, or at least attend to him given his drive to continue self-administering the dangerous formula. Krane discovers the identity of the drug store murderer Eddie Dutton (Kim Coates) through his sensory reclaiming of the victim's spinal fluid and also concludes from specific mannerisms of the criminal that Dutton is the man who killed Krane's wife. Police Inspector Don Bresler (Peter Coyote) intervenes to prevent Krane from discovering more about the past of Eddie Dutton, but Detective Stewart Gleick (Chris McDonald) initially against Krane begins to see some possible miss-doings in the Police force and takes steps to support Krane and find the killer of his wife. When Krane gains possession of his own wife's spinal fluid and with Dr. Briggs assistance injects himself with it, the results bring about the discovery and involvement of more than he considered.