Jack O'Brien comes to the mining town of El Dorado with nothing but his pluck and his music. Biddy Malone was the first to hear his singing, and it won a place for the lad in her heart and a job at her woodpile to pay for his board, while Mary, who lived with Biddy, looked and listened, and learned to love the big singer. Hardpan Henry, who owned the Lucky Strike claim, and who was really Mary's father, also hears the troubadour's song, took a fancy to the lad and showed him the sights of El Dorado.