At Davis Memorial Hospital, university professor John Rogers and his wife Paula are devastated when she suffers a second miscarriage, which results in her permanent sterility. Family friend and physician Dr. Clifford "Cliff" Frazer cautions John that it will take Paula some time to get over the trauma. After returning home, Paula visits other physicians without John's knowledge, hoping to refute Cliff's prognosis, but only has it confirmed. Meanwhile, John has been put forward as the university's new dean. Because of a clandestine doctor's appointment, Paula is late the night of the John's reception by the trustees, and hurries away in her car. The speeding Paula grows annoyed when she comes upon a dawdling pickup truck driven by an elderly farmer, Raymond Bascom. Passing Bascom, Paula finds herself close behind a larger truck and is unable to respond quickly when it swerves to avoid hitting a small boy in the road. Paula's car strikes the boy and, terrified, she stops and rushes over to him. Meanwhile, Bascom pulls over and accuses Paula of being inebriated and rushes the boy to the hospital as Paula protests. At the reception, Cliff notices Paula's agitated state before she hastens away to telephone several hospitals to track down the boy. She discovers that he is at Davis Memorial and that Bascom has reported the accident as a hit-and-run. Later as Paula and John drive home, Paula attempts to tell John about the accident, but desists when he discusses his new position enthusiastically and explains that there must be no scandal connected to his name to insure his confirmation. Later that night at the hospital, the investigating police detective, Lt. Dargen, identifies the boy as orphan David "Davy" Larson. Under further questioning, Bascom insists that the woman driving the car was drunk and recalls having seen a university sticker on the car. The next morning the information is published in the paper and, distraught, Paula visits Cliff hoping to find a way to see Davy. When she asks to volunteer at the hospital, Cliff agrees. Meanwhile the police match up the paint from Davy's clothes to the particular model and year of car the Rogerses car. Paula begins her volunteer work immediately at the hospital and manages to see Davy from afar. At home she remains tense and fretful, but reveals nothing to a concerned John. Some time later, working in the pediatric unit, Paula comes face to face with Davy and is stunned to learn from a nurse that the accident has left him incapable of speech. Cliff tells her that Davy is otherwise normal and that he can be helped with constant therapy. After Cliff asks Paula if she is interested in assisting Davy, she decides to ask John, who initially resists the notion of bringing a "freak" child into their lives. When he consults Cliff, however, the doctor tells him that Paula may well become neurotic if not allowed the opportunity to help Davy, and so John agrees. Paula brings Davy home, and John is at first distant, but soon finds himself genuinely absorbed in the boy's care. Cliff instructs Paula on Davy's speech therapy, and after she works diligently with him, Davy is able to say single words. One day, Lt. Dargen visits Paula under a pretext and Paula introduces Davy, who manages to say hello. In the driveway Dargen notes the scratches on Paula's car and tells his partner the accident case is wrapped up. John and Paula decide to fully adopt Davy, but one night, while dressing for a party, Paula wears the same dress and jewelry as the night of the accident and is startled when Davy recoils from her. The next day Davy's teacher tells Paula that Davy is withdrawn and sullen. Paula asks Davy if he has recalled the accident, and he nods and glares hatefully at her. She explains it was an accident, but Davy remains angry, until Paula tells him that the only way anyone will ever know of her guilt is for him to continue learning to speak. Davy begins working extra hard at his therapy, determined to accuse Paula. Meanwhile, Bascom, having heard of Davy's adoption, drives out to meet Paula and is aghast when he recognizes her, believing that she has taken Davy only for the purpose of covering up her guilt. When he attempts to take Davy away from her, the boy falls down the steps in the struggle. Paula summons Cliff and John, and explains everything about the accident and that she only wants Davy to finish learning to speak. Dargen arrives, as Bascom has filed charges against Paula, but Cliff takes them all to the recovered Davy and asks him if he has anything to say. Davy breaks down and calls Paula "mother." Dargen assures the Rogers their case will probably face no difficulties and Davy's adoption will go through.
