Adaptation of the novel by Mary Wesley.
A woman who has been institutionalized for 60 years for the "crime" of not conforming to the 1920s image of what a proper young woman should be (in other words, she did what she wanted and didn't care what anyone else thought about it) is finally released to the custody of her family, consisting of her grand-nephew and his family. At first she keeps a self-imposed distance from the relatives, but she soon finds herself coming around to her nephew's wife, a free spirit who is under the thumb of her cold and controlling husband
Caroline is to be wed to Sir Ralph and invites her sister Barbara to be her bridesmaid. Barbara seduces Ralph, however, and she becomes the new Lady, but despite her new wealthy situation, she gets bored and turns to highway robbery for thrills. While on the road she meets a famous highwayman, and they continue as a team, but some people begin suspecting her identity, and she risks death if she continues her nefarious activities.