The Onion Field tells the tragic true story of happenings in Los Angeles, 1963. Ian and Karl are two police officers. One night, on patrol duty, they are kidnapped by two petty thieves who drive them into the country and leave them in an onion field. Karl escapes, but Ian is shot for which the thieves are eventually arrested, tried and sentenced to death. When a successful appeal grants them a retrial and for seven years Karl is repeatedly called to the witness box, he becomes haunted by the nightmare of events that surrounded the onion field.