In 1802, in the backwoods of Maryland and Virginia, young physician Dr. Alexander Meade is being hanged for grave-robbing, a practice necessary for his medical experiments, when members of a notorious band of thieves save him from death and deliver him to their chief, Big Jack Horner. Although Big Jack is feared by all who know of his reputation, a glimpse of his generosity shows through his rough-hewn exterior after Meade successfully patches up his wounded leg. As a token of his appreciation, Big Jack offers Meade an antique timepiece, but the doctor refuses, asking only to be permitted to do his work and to have his books returned to him. Eager to please Meade, Big Jack goes to Marlborough County and engages the sheriff in a gunfight to gain possession of the doctor's seized belongings. Later, Big Jack presents Meade with a pretty young woman named Patricia Mahoney, who was taken by Big Jack against her will to be Meade's bride. Patricia, however, thinks that Meade had requested their arranged coupling and shows contempt for him when they meet. Meanwhile, Valentine, one of Big Jack's men, spreads the news about Meade's crimes. Big Jack rises to Meade's defense, however, explaining that the only difference between their profession and his is that they "rob the living and he robs the dead." Big Jack continues to insist that Meade stay by his side, and now that Big Jack knows that he can repay his debt to Meade by furnishing him with dead bodies on which to experiment, he considers killing the sickly men in his gang in the name of science. Meade, fearing Big Jack's overzealous approach, insists that the corpses he work on be those of men who died from natural causes. One evening, Meade escapes with Patricia and returns her to her home in Montaville. When Meade realizes that he has fallen in love with Patricia, he decides to stay in Montaville and set up a practice. Big Jack, meanwhile, has become distraught since his pal Meade escaped, and vows to find him and bring him back. Disguised in clothing stolen from a couple they pass in a stagecoach, Big Jack and his wife, Flapjack Kate, make haste for Montaville. There a gun battle between Big Jack's men and half the town ensues when Meade orders Big Jack to leave. Meade is taken by force to Big Jack's camp, where he demands that Big Jack return the money he stole from the Montaville bank. Big Jack initially rejects Meade's demand, but after Flapjack Kate helps Meade escape, he rethinks the method he is using to win Meade's friendship and returns the money to the bank and makes amends with Meade. Later, while Meade undertakes a delicate abdominal operation on Patricia's ailing sister Sarah, Patricia's father, the Mayor of Montaville, leads a posse to drive the grave-robbing doctor out of town. As Meade races against time to save Sarah's life and his own, Big Jack arrives with his men and succeeds in keeping the posse from storming Sarah's house. However, when the men in the posse mistakenly think that the operation has failed, they engage Big Jack and his men in a gunfight. Big Jack is mortally wounded in the battle, but before he dies he presents Meade with a token of his friendship: the timepiece the doctor had initially refused to accept when he successfully operated on his wounded leg.