Dave Jennings, Richard Widmark, is a Los Angeles–based businessman whose days are swallowed by deals and deadlines, leaving little room for the vibrant, precocious Gus George Winslow. Gus constantly creates little storms just to snag his father’s attention, and after yet another costly mess is cleaned up, Dave orders his long-suffering secretary, Ivy Tolliver Joan Banks, to find a new nurse for Gus before heading out on a business trip. On his return, he discovers that Ivy has placed Gus in the Playtime School, and he must meet Lydia Marble Joanne Dru to enroll his son properly.
Rushed as ever, Dave tells Lydia he’ll pay whatever it takes to keep Gus in line, but Lydia explains that true progress comes from parental participation in the child’s education at Playtime. Dave is astonished by how well Gus responds to Lydia’s structured guidance, especially after a moment when Gus smacks a schoolmate. Despite initial reluctance, Dave decides that the boy can benefit from Lydia’s tutelage and agrees to keep him at Playtime.
Over the next three weeks, Gus grows more content and well-behaved, and Lydia’s methods begin to pay off. On the scheduled parent participation day, Dave sends a truckload of toys to the school instead of showing up himself. Lydia returns the toys with a firm note, reminding Dave that substitutes for his attention aren’t enough. When Dave shows up to protest, Lydia assumes he’s there to help, and their interaction marks a turning point in both Gus’s life and Dave’s view of parenting.
Dave admits to Lydia that he has fallen in love with her, and while Lydia’s feelings mirror his, she cautions that his emotions may be tied to his reliance on her for Gus’s care. That night, Dave comforts a frightened Gus by letting him sleep in his own bed. In that moment, he realizes he no longer needs Lydia merely as a teacher of child-rearing; he understands that his love for Lydia is about more than dependency. Lydia welcomes this revelation, and their connection deepens as she begins to see him as a partner in fatherhood.
As time passes, Dave becomes a devoted father, and his relationship with Lydia blossoms into an engagement. Then, on Gus’s birthday, Dave’s ex-wife Joyce Jennings Audrey Totter arrives with troubling news. Joyce, who has always been money-minded, claims a Mexican divorce may not be legal and asks Dave for support. Dave’s lawyer, Farley Norris Regis Toomey, confirms the unsettling development, but Dave, furious at Joyce’s abrupt return, refuses to provide funds for a contested divorce.
Determined to win regardless of Joyce’s claims, Dave ignores well-meaning pleas from friends to consider Gus and walk away quietly. He hires private detectives to build a case against Joyce, and he retreats to his new beach house to rest. Unbeknownst to him, Lydia and Gus are there too, and when Joyce’s lawyer accuses Dave of adultery and names Lydia as a co-respondent in court, the public fallout threatens Lydia’s school and her credibility.
Lydia confronts Dave, accusing him of valuing wealth over his son, and ends their engagement. The courtroom drama continues, and Farley Norris proves that Joyce had abandoned Dave, triggering a divorce that the judge grants. However, Joyce wins custody of Gus, a devastating blow for Dave. Heartbroken, he drives to Joyce’s hotel and Gus pleads to stay with him. Realizing that Gus means more to him than anything else, Dave offers everything he owns in exchange for permanent custody of Gus.
As he returns to the car, Lydia appears, promising to help him fight for their son. She reassures him that the matter can still be resolved in a way that keeps Gus in their lives. With a renewed sense of purpose, Dave embraces Lydia and Gus and, in a quiet moment of resolve, asks Lydia if she can pay for lunch, signaling a new chapter where family and partnership might guide them toward a shared future.
