 Ambitious Helen Sherman (Ida Lupino) pushes her talented younger sister Katherine (Joan Leslie) into marriage with broken down song-and-dance man Albert Runkel (Jack Carson) so that the two women can leave the dirty steel town where they live. Runkel s partner Paul Collins (Dennis Morgan), however, sees through Helen s plan. Helen continues driving her sister s career and eventually Katherine becomes a star on Broadway, while Runkel and Collins  act flounders. Unable to cope with his wife s success and Helen s efforts to destroy their marriage, Runkel kills himself. Success soon goes to Katherine s head and she becomes a fast-living party girl. Time passes and Helen and Katherine run into Paul, now a successful band leader. He and Katherine soon fall in love. The two sisters eventually have a showdown on opening night of Katherine s latest show when Katherine discovers that Helen is also in love with Paul.