Susan Selky, portrayed by Kate Nelligan, is a distinguished English professor residing in a quaint Brooklyn brownstone with her young son, Alex, portrayed by Danny Corkill. One fateful morning in March, Susan bids farewell to Alex as he heads off to school, which is conveniently located just two blocks away; however, her heart sinks as she watches him disappear around the corner.
As the day unfolds and Susan returns home after imparting knowledge to her students, she becomes increasingly anxious when Alex fails to arrive at his regular time. In a fit of worry, she reaches out to her neighbor and friend, Jocelyn Norris, played by Stockard Channing, only to discover that Alex never made it to school at all. This alarming revelation prompts the immediate attention of the NYPD, with Lieutenant Al Menetti, portrayed by Judd Hirsch, leading the charge. Susan undergoes intense questioning regarding her life and her son’s whereabouts, with the investigation quickly honing in on Susan's estranged husband, Graham, portrayed by David Dukes, who seems to be missing.
When Graham finally appears, he presents a solid alibi that clears him of any suspicion, but the investigation seamlessly draws the interest of the media within New York City, making Susan the focal point of public discourse as citizens band together to distribute missing person posters of Alex. As the days pass, Susan starts to face criticism for allowing her son to walk to school solo. She even agrees to take a polygraph test, which ultimately vindicates her, confirming she is not involved in her son’s disappearance.
Several leads emerge during the investigation, including various sightings of Alex believed to be in the back of a characteristic blue 1965 Chevy. Despite bringing in a psychic for assistance, each lead leads to nowhere, leaving Susan increasingly disheartened. As the months drag on, the investigation begins to lose its momentum, with budget cuts forcing Lieutenant Menetti to dismantle the command center that had taken over Susan's home. This shift in dynamics creates tension as Menetti finds himself pulled in different directions amid other urgent cases, yet the Selky case remains a top priority for him.
In a desperate bid for answers, Graham takes matters into his own hands when he receives a ransom call, leading him to an isolated meeting where he is ambushed and sustains serious injuries—resulting in a necessary hospital stay. On the Fourth of July, a potential breakthrough happens when Susan's house cleaner, Philippe, played by Keith McDermott, is arrested due to damning evidence linking him to Alex’s disappearance. A pair of Alex's bloody underpants emerge from Philippe's apartment, but he asserts his innocence, claiming he merely used them to staunch bleeding from a kitchen accident. Susan's instinct tells her that Philippe is not guilty, yet Lieutenant Menetti insists on moving forward with the case based on the physical evidence he cannot divulge.
As media outlets lose interest in Philippe’s arrest, Susan faces growing pressure to relinquish hope for her son's return, with even her friend Jocelyn nudging her to come to terms with the heartbreaking possibility that Alex might not be coming home. Nevertheless, Susan clings to her conviction that her son is alive. Then, an unexpected phone call from a woman named Malvina Robbins in Bridgeport, Connecticut, heralds a flicker of hope as she claims knowledge of Alex’s whereabouts. Menetti, however, dismisses the lead, branding Robbins as merely a “lonely old booby," and announces the impending trial for Philippe.
On a day of respite, Menetti finds time to take a drive with his own son, David, played by David Simon. When fate guides them toward Bridgeport, Menetti accepts a diversion to look into the tip, hoping to put an end to Robbins' claims that have disturbed Susan. As he arrives at Robbins' address, he notices a blue Chevy parked at a neighbor’s residence—realizing the potential connection to the earlier sightings. With the shocking revelation that Robbins might be telling the truth, Menetti hastily contacts the Bridgeport police.
In a miraculous turn of events, they locate Alex, who is found safe and sound with his captor—a desperate man simply seeking assistance to care for his elderly mother. Menetti escorts Alex back to New York City with a police convoy in tow, keen to reunite him with his mother, while media outlets bubble with excitement over the news. As Susan returns from grocery shopping, her world lights up as she witnesses her beloved son emerging from Menetti's car amidst a gathering crowd of hopeful supporters and reporters. The poignant moment of reunion between mother and son introduces an emotional climax that encapsulates Susan’s unwavering determination and love throughout the agonizing journey.
