Jackie is the perpetually adolescent mother of two grown children - daughter Lee and son Jeff - who are in their early 20's. In spite of the fact that fourth husband Robert is a good provider, good step-dad, and all-around good sport about Jackie's rather wild ways, Jackie is intent on divorcing him although she seems to bear the man no resentment. It just seems that her only reason is that it's time for a change, much like an impulse to buy a new hat. Both children are upset about her decision since they have great affection for Robert. However, daughter Lee has just arrived home from school and decides to accompany her mother to Reno to look after her. On the train west, Lee meets a young mining engineer, Tom, who is headed to a job interview in California. The two hit it off and a romance buds.

Jeff et Lee Millet sont mécontents que leur mère Jackie, qui a déjà plusieurs fois divorcé, soit en instance de divorce de leur beau-père, Robert. Jackie est considérée comme une femme moderne, dont l'apparence jeune amène les gens à croire qu'elle est la soeur de sa fille. Lee accompagne Jackie à Reno, où elle a l'intention d'obtenir le divorce et célébrer cela avec d'autres femmes divorcées. Dans le train elle fait connaissance de Tom Wood, un jeune ingénieur de la classe ouvrière, sérieux qui va à San Francisco pour son premier emploi.