A buddy flick pairing a grumpy old man with a charmingly innocent robot: what’s not to like? Especially when, as in the case of Robot & Frank, the grumpy old man is played by Frank Langella and the robot (named Robot) is cute enough to look like it jumped right out of a Disney film. Indeed, Robot & Frank has far more in common with Wall-E than 2001: A Space Odyssey — Robot is about as far from HAL as it is possible to get. And he’s a hell of a lot more useful.

The premise is simple: It’s the near future, and Frank is an elderly man whose mind isn’t working as well as it used to. Since he lives alone, his adult son decides to bring him a robot who functions as a kind of live-in caregiver, cooking meals, setting a routine, and generally providing encouragement and support. Frank, who is the most crotchety old man to steal the screen since Walter Matthau’s Max Goldman in Grumpy Old Men, hates the robot at first and does his best to make things unpleasant for both of them. Once he realizes that the two could make a great team, however, he quickly warms up to his loyal companion. Frank, it seems, used to be a pretty successful jewel thief, and Robot, with his perfect memory and ability to break codes, is an ideal partner. When the two start pulling heists together, which Robot only agrees to because having a “project” is necessary to Frank’s mental health and happiness, their friendship blossoms.

Robot & Frank is a light and in many ways inconsequential story, but the film fulfills its pleasant purpose beautifully. Set in a quaint, quiet New York town where the future is signified by little more than Robot and a library that’s being digitalized, Robot & Frank is a comforting kind of movie, despite its honest depiction of the loneliness of aging. The smooth cinematography matches the story’s meandering pace. Both move the film’s subjects along so calmly that one could be forgiven for thinking that hardly anything happens from start to finish. Even the revelation that Frank spent 16 years in prison for stealing diamonds is offered in such an understated way that it could be just another trick of Frank’s aging brain (although it isn’t — and don’t worry, that’s not a spoiler).

Much of this soothing feeling comes from Robot (voiced by Peter Sarsgaard), whose only directive is to keep Frank healthy and functioning. In many ways, he is like a capable, matronly nurse, cooking his charge low-sodium dinners, waking him up at seven each morning, taking him on long walks through the woods for exercise. But unlike a human nurse, Robot never gets frustrated, tired, or dissatisfied with his work. He is, in his robotic way, completely accepting of Frank even when he is at his most unlovable, and it’s easy to imagine what a novelty that must be for someone who spent much of his adulthood on the wrong side of the law. Sarsgaard’s voice acting manages to convey the very human qualities of compassion and naivete, while maintaining Robot’s distinct otherness. No matter how close Frank feels to Robot, and no matter how sincere Robot sounds, we never forget that he is simply a machine. This makes the relationship between the two all the more poignant, especially as Frank begins to come to life again under Robot’s care.

The high-profile cast is outstanding, with James Marsden as Frank’s long-suffering, dutiful son, Liv Tyler as his flighty, empty-headed daughter, and Jeremy Strong as Jake, the villainous destroyer of “printed information” who is taking over the library. He deserves special recognition for being so disgustingly condescending and whiny that you wish Frank would just give him a good slap. The impeccable Susan Sarandon, exuding warmth and loveliness, is Frank’s librarian crush (Sarandon is accompanied by an old-looking, boxy robot with a distinctly electronic voice — guess library funding is as poor in the future as it is now). She and Langella have a natural, easygoing chemistry, and they interact with their non-human co-stars as easily as they do with each other.

The only disappointment comes toward the end, as the film reaches its inevitable, bittersweet conclusion. Without spoiling the story, all we can say is that there seems to be a decent-sized plothole there, the only purpose of which is to tug just a little bit harder at the heartstrings.

But overall, that is a small criticism. For a film this full of dramatic superstars, Robot & Frank has surprisingly modest ambitions: to offer a little tale of companionship in old age. Sometimes, that’s enough.