Laurence Olivier plays a young Londoner implicated in a brutal murder. According to the rules of British law, he is permitted 21 days of comparative freedom from the time of the first hearing to the time of trial -- provided he does not leave London. As the three weeks pass, Olivier falls deeply in love with girlfriend Vivien Leigh, who at first believes in his innocence. But as the deadline approaches, Olivier's mood swings and erratic behavior shakes Leigh's faith in him. Scripted by British suspense expert Graham Greene, 21 Days Together was originally released under the simpler title 21 Days.