Diagnosed as having a fatal brain tumor, insurance investigator Paul Cameron (George Kennedy) provides for his family by confessing to the murder of a wealthy industrialist. Carefully constructing a case for his prosecution, he negotiates under a pseudonym for the sizable reward offered by the victim's associates. Despite the defense of attorney Mario Gambretti (Eli Wallach), Cameron is convicted. After collapsing while leaving the courtroom Cameron is subjected to successful laser beam surgery. Fully recovered, Cameron faces imprisonment for a crime which he did not commit. Informed by Gambretti that a new trial is impossible without further evidence, Cameron escapes from the hospital and stalks the real killer.