After being released from prison, "Australia Joe" attempts a bank robbery and escapes. Out west, his gang robs the town-hall and steals papers for some mysterious person "higher up." Joe learns the identity of this man and prevents his marriage to the daughter of a man he has framed.

Left in the care of his half-breed brother, Buck, by his dying mother, Wallace Layson has no knowledge of his family history. His father, knowing that his son will inherit a ranch on his 21st birthday, tries to secure the property for himself by persuading a dance hall girl to come between the boy and his fiancée. When Buck learns of the plan he decides to foil it without his half-brother knowing.

Ruth Holt, owner of a boardinghouse in a small college town, lives with her pretty niece "Sweet Lavender," who believes that Ruth is her mother. When boarder Clem Hale, president of the freshman class, is the victim of a prank played by several of his classmates, Lavender rescues him and the two fall in love. Clem's guardian, Horace Weatherburn, becomes concerned about his ward's adoration for a "commoner" and arrives to break up their romance. Ruth, who recognizes Washburn as Lavender's real father and the man who brought her sister grief, strongly opposes the match and sends Lavender off to boarding school. Upon learning that Clem is seriously ill, Lavender runs away to comfort her sweetheart and, in her plight, faints by the side of the road. Weatherburn finds her and is so touched by her concern, that he relents his previous disapproval. Ruth then reveals Lavender's parentage to her father who offers his blessing to the couple.

At a party thrown at the Metcalf estate, the Marquise D'Irancy's Sultana diamond disappears when the lights go out during a power failure. Suspected of the crime is William Kirkland, the wastrel son of the wealthy Kirkland family, but William's sister Diana comes to his defense. Aiding her in the investigation is Clamp, a wandering peddler.