The Marchioness of Castlejordan was so desperate to have sons that she raised her three daughters--Tommy, Willie and Noel--as boys. While on a trip to London the girls change into female clothes, but the youngest of them Tommy, changes into boys clothes and gets into a fight in a music hall, knocking out his opponent. Pursued by an angry mob, Tommy jumps into the nearest passing car, which happens to belong to Lord Litterly, who admires the "boy`s" pluck. Litterly soon discovers that Tommy is actually a girl, and also discovers something else--she is a relative. Complications ensue.