Recently, the University of Connecticut was training a robot called Nao to care for elderly people. One day, artificial intelligences may replace specialized caretakers. Robot & Frank envisions a “near future” where this seems to be a standard practice. When someone grows too old to watch out themselves, a machine can do the watching for them. This is a nicely realized world that’s convincing as one that could conceivably be on our horizon, a world where books are extinct and phones now look like glass cards.

Frank (Frank Langella) is a man stranded in this strange new world, a relic of the times of paper. His mind is starting to go, although he stubbornly refuses to acknowledge it. At first, the helper robot his son (James Marsden) gets for him, known only as Robot (voiced by Peter Sarsgaard), is just a nuisance. That is, until Frank realizes that Robot’s mechanical dexterity allows him to easily pick locks. Frank is a retired cat burglar, and he sees in Robot an opportunity to get back in the game. He hopes to impress a local librarian (Susan Sarandon) who’s watching her profession fade away.

The movie is being sold as if it’s a whimsical, good-natured “man and his robot” tale, like a live-action Up with C-3PO instead of a talking dog. But it actually has a ponderous solemnity in its heart (to be fair, so did Up). Director Jake Schreier doesn’t try to make mental degeneration look cute, and every moment that Frank forgets where or when he is strikes an effectively tragic chord. This is a story about one last hurrah, and of letting go of past youth.

Langella is phenomenal at conveying that kind of semi-lucid gravity. Anyone who has had a parent or grandparent go through the same situation will recognize the verisimilitude in his performance. But he’s also great at playing the weary but clever grump. Even if that aspect of the character falls somewhat into cliché, Langella makes it work. And when bouncing off Robot, he’s a total delight, as his coarse hard-headedness rubs against the machine’s stoic professionalism.

Robot is a difficult character to pin down. Unlike the portrayals of AI in more mainstream science fiction film, it is repeatedly established that he does not have a personality, nor a “soul.” Robot is a tool; a sophisticated, thinking tool, but a tool nonetheless. Frank, though, comes to grow attached to Robot, eventually thinking of him as a friend. But the movie doesn’t have Robot develop emotions or anything like that, and he can never return Frank’s affections. The audience is only attached to the pair so much as Frank is attached to Robot. It’s odd for the movie to ask us to care about what happens to Robot even as it repeatedly reminds us that it isn’t, in any philosophical sense, a “being.”

While the title characters are fun to hang around, the movie’s supporting cast isn’t as interesting. Marsden has some good moments as Frank’s son, but Liv Tyler is wasted as Frank’s daughter, showing up mostly for an extended sequence that doesn’t really have much of a point. The romance with Sarandon’s character is not just undercooked, but ends in a twist moment that’s as nonsensical as it is unnecessary. These tertiary characters orbit uselessly around the central duo, and, with the exception of Marsden’s, the movie might be better off without them.

Robot & Frank is a pleasant, funny, cute little film that could be better if it didn’t drift so much. The plot is a limp series of threads sometimes tripping each other up, sometimes just up and vanishing. Ideas come and get dropped, scenes without any narrative motivation drift by, and things just sort of happen instead of occurring in any organic way.

This is a worse way to distance the viewer than not giving Robot a personality. When things go south for Frank, there’s very little reason to feel invested in the outcome. And it results in a final note that’s meant to be uplifting but instead feels contradictory. Frank is shown to have a troubled relationship to his son, and it’s “mended” in a way that isn’t earned at all. It’s going through the motions without performing the dance. And with the exception of Frank’s interactions with Robot, that’s a good way to describe the whole movie.