Forensic psychiatrist Jo Beckett's speciality is the psychological autopsy - an investigation into a person's life to determine whether a death was natural, accidental, suicide, or homicide. When Jo is asked to do a psychological autopsy on a living person - one with a suspect memory who can't be trusted to participate in his own medical care - she knows all her skills will be put to the test. Jo is called to the scene of an aircraft inbound from London to help deal with a passenger who is behaving erratically. She figures out that Ian Kanan has got anterograde amnesia, and can't form new memories. Jo finds herself racing to save a patient who can walk and talk and yet can't help Jo figure out just what happened to him. Suddenly a string of clues arises, something to do with a super deadly biological agent code-named "Slick", a kidnapping, and a secret partnership gone horribly wrong. Jo realises Kanan's addled mind may hold the key to preventing something terrible from happening in her beloved San Francisco. With time running out, she will have to get deeper into the life of a patient than she ever has before, hoping the truth emerges from the fog of his mind in time to save her city - and herself.