Based on the life of Libby Holman, a Broadway singer marries a millionaire, who regrets he gave up his fiancé and kills himself.
Granny (May Robson) asks Ned Riley (William Powell) to get her granddaughter Mona Leslie (Jean Harlow) out of jail so she can perform at a benefit. Bob Harrison (Franchot Tone) is alone in the audience. Mona sings "Reckless" and dances. As president of the charity Bob invites Mona to supper and lets the rest go; but Ned has police take Mona back to jail. Bob meets her when she gets out and takes her to a charity bazaar, where he kisses her. Ned shows Mona her new horse. She falls asleep in a hammock while he proposes. Mona goes on a yacht with Bob.
Ned loses at poker, sees news that Mona eloped with Bob Harrison, and gives a gold ring to his assistant Blossom (Nat Pendleton). Mona wakes up happy; but Bob goes down and hits a reporter, who says he betrayed his fiancée Jo Mercer. A telegram says his father is "bitterly disappointed." Ned gets drunk. On the train to the Harrison home Mona sees the news story. Mr. Harrison (Henry Stephenson) criticizes his son Bob. Mona meets Josephine Mercer (Rosalind Russell) and says she didn't know Bob was engaged. Jo returns a diamond ring to Bob and praises Mona. Bob fights with his brother Paul. Bob wants to go back to New York, but Mona suggests they stay and face it. Ned is being evicted, and his lemonade-stand partner Eddie (Mickey Rooney) offers him money.
Ned goes to a race-track near the Harrisons and meets Mona and Bob. Jo says she is engaged to Ralph and weds him. Bob gets drunk and asks why she did it. Mona overhears Bob say she trapped him into marriage; he loves Jo. Ned comes in and tells Mona to dance. Bob stops the music and is prevented from fighting Ned. Mona tells Ned she is going to be a mother. Drunk, Bob calls on Ned and Mona. After they put him to bed, he shoots himself. Society blames Mona and Ned. Mona gives birth to a boy, and Harrison sues for custody. Mona offers him her inheritance for the boy. Harrison offers to help support the boy, but she declines. Ned borrows to back Mona's show, getting contributions also from Granny and Blossom. Despite protests Ned opens the show with Mona singing "Hear What My Heart Is Saying." Many boo while some clap. Mona explains how she tried to make Bob happy and all she has now is her ability to sing and dance. She sings, and the audience applauds. While Mona sings "When I'm In Love," Ned proposes from behind the curtain.
Though Virginia Verrill sings for Harlow, I found this film quite entertaining and moving. Mona is a sincere and strong character; Ned is friendly and humorous; Jo is understanding; only Bob is weak and confused; even Harrison is brought around with the audience by Mona's integrity.