Set in a not-so-distant future, Frank (played by Frank Langella), an aging ex-convict and thief, finds himself grappling with significant mental decline and dementia while living alone. His son, Hunter (portrayed by James Marsden), a busy attorney with his own family, feels the weight of his weekly visits to Frank’s home and is increasingly anxious about the idea of placing his father in a permanent care facility. To avert this, Hunter purchases a robot companion, voiced by Peter Sarsgaard, designed specifically to offer Frank therapeutic support through a structured daily routine, along with cognitive-enhancing activities, like gardening.
At first, Frank is skeptical about the robot's role in his life. However, his perspective shifts dramatically as he discovers that the robot has no moral constraints when it comes to differentiating between lawful leisure and criminal activity, making it a perfect accomplice in Frank’s desires. Together, they hatch a daring plan to impress the local librarian (played by Susan Sarandon), culminating in a heist to steal an antique edition of Don Quixote from the library, which is in the midst of being transformed into a community center as print media loses its luster.
Simultaneously, Frank’s daughter Madison (played by Liv Tyler), who is away on a philanthropic mission in Turkmenistan, learns about the robot and makes a hasty return home. She vehemently opposes the robot's presence, viewing it as ethically problematic, but Frank remains adamant about retaining his mechanical companion. Together, they plunge into another audacious caper, this time targeting Jake (Jeremy Strong), the wealthy developer overseeing the library renovation. The story intensifies as the police begin to take notice, interrogating Frank while he pretends to be gravely ill in hopes of luring Hunter back to their hometown.
As the stakes rise, Frank confronts a difficult decision about whether to erase the robot’s memory, even as his own cognitive abilities continue to falter. A startling revelation hits Frank when he discovers that the librarian he intended to impress is actually his ex-wife, whom he had forgotten due to his mental state. Upon returning home, the robot persuades him to delete its own holographic memory, explaining that it exists solely to assist Frank.
In a final turn of events, Frank finds himself at a "Brain Center," a facility designed to help him cope with his dementia. The twist reveals that the stolen jewels remain undiscovered; in a heartfelt note to Hunter, Frank informs him of their hiding place beneath the tomato plants in his garden, cultivated under the care of the devoted robot.
