An opera singer goes undercover in the Canadian wilderness to hunt for her criminal brother.

In Montreal, Canada, opera star Marie de Flor gives a masterful performance of Gounod's opera Romeo et Juliette . Following the show, Marie tells her maid, Anna Roderick, that she is not in need of romance because she has her work, fame and money. She concedes, however, that the only man she ever truly loved is her brother, John Flower, who is serving a jail sentence for participating in a holdup. Upset by the recent news of her brother's parole rejection, Marie decides to seek a pardon for him by courting the favor of the visiting premier of Quebec. As Marie is about to request the premier's help, however, she is visited by Boniface, a mysterious Indian half-breed, who informs her that John has escaped from prison, killed a Mountie in a fight and is now a wounded fugitive in need of her financial help. Marie decides to follow Boniface to his mother's home in the woods, where John is hiding, and they leave immediately. While Marie and Boniface begin their journey north, Sargeant Bruce, a Royal Canadian Mounted Police officer, receives an assignment to find John, who is believed to be hiding near Lake Shibuga. Bruce is given a description of the fugitive and is told that the man has no known relatives. When Boniface and Marie arrive at the nearest outpost to Lake Shibuga, Boniface robs Marie of her money and deserts her. After an unsuccessful search for Boniface, the penniless Marie tries to earn money by singing at a local saloon. The opera singer, however, is soon humiliated by the patrons of the saloon and forced to turn her song over to Belle, the tavern favorite. Following her brief saloon stint, Marie is approached by Bruce, who compliments her singing. Though Marie tells Bruce that her name is Rose-Marie, Bruce pretends not to know her real identity while questioning her about her stolen purse. Eventually, though, Bruce admits that he knows who she is and that he recognized her immediately. Marie tries to keep Bruce out of her affairs, but Bruce insists on escorting her to an Indian camp, where he believes that the man who stole her purse is likely to be found. While crossing a moonlit lake on their way to the Indian camp, Bruce, who has fallen in love with Marie, tries to woo her with a sweet serenade. Marie finds Boniface at the Indian camp and threatens to turn him over to the police if he does not resume his job as her guide. Later that night, after serenading Marie once again, Bruce connects Marie's last name, the Spanish word for "flower," with that of the escaped convict. He rushes back to her room, but discovers that she has fled. Bruce then follows Marie's trail, keeping a safe distance once he finds her, until she falls into a lake and begins to drown. While Bruce saves Marie, Boniface slips out of Marie's sight for the second time. Marie and Bruce camp for the night by the lake, where he explains the legend behind the Indian love calls they hear in the distance. They then compose their own Indian love call and end it with a kiss to seal their love. On their last night together, Marie suggests to Bruce that he quit his job as a mountie and begin a singing career, but Bruce insists that his place is in the woods. Before they go their separate ways, Bruce promises Marie that he will always respond to her love call. Although she is not aware of it, Marie is followed by Bruce after they bid each other farewell. Marie is soon reunited with Boniface, who takes her to her brother. John is glad to see Marie, but appears to be overly eager to spend her money to go China. The happy reunion is soon disrupted when Bruce arrives and arrests John. The sobbing Marie begs Bruce not to take him away, and despite her attempt to stop him by singing their "love call," he remains loyal to his oath and takes John away. Time passes, and Marie resumes her singing engagements and performs in the Giacomo Puccini opera Tosca . The play proves too much for her, though, and she collapses on stage in the final act. Six months later, while recuperating at a mountain cabin, Marie sadly sings the "Indian Love Call." When she reaches the refrain of the song, Bruce enters from the foyer, where he has been listening, and sings with her. The reunited lovers finish their song and kiss.