The fiery, impulsive, yet pure-hearted Lasca lives in a Mexican settlement near the Rio Grande with her twin brother Ricardo and their aunt. She falls in love with cattle rancher Anthony Moreland, whose teasings bring out her jealous temper, but Moreland, although fond of Lasca, thinks of her as a child. Seeing the flirtatious, though engaged, Clara Vane fall in love with Anthony, Lasca, in a vicious fit, stabs his wound and begs forgiveness.