Such a delicate film is The Namesake, and such a sweet relief from the exceptionally draining run of crap I'd gotten myself stuck in recently! It's a simple thing, but made with obvious care by the perpetually underrated Mira Nair, and its gentle humanism is like a breeze of fresh spring air. Ouch, that was a Hallmark card of a sentence. Forgive me.

But anyway, The Namesake: a lovingly observed story of a family of Bengali immigrants in New York, 1977-2002. As well as just about the worst-marketed film thus far into 2007: the trailers and posters and everything all shriek that this will be all about Kal Penn in teh drama, which is thrillingly not the case: Penn doesn't even appear until somewhere around the thirty-minute mark. No, this is an ensemble film through and through, and one of the most well-chosen ensembles of recent vintage: Bollywood stars Irfan Khan and Tabu as Ashoke and Ashima Ganguli of Calcutta, Penn and Sahira Nair as Gogol and Sonia, their American-born children, and a host of new-to-US-theaters faces filling out every corner. And every last damn one of them - even, I don't really want to admit, Kal Penn - are fantastic.

One of the things I've respected about all of Mira Nair's films that I have seen (not enough) is that she has so continuously avoided journeyman work. Every one of Nair's films is personal and important to her; and none so much as The Namesake. This is of course unsurprising: a story about the conflict between ethnic pride and American assimilation must cut very close to home for a filmmaker who has carved out a career of making idiosyncratic stories about social outsiders in the United States.

This is a film made with obvious care and affection, both for the specifics of the story and the broader society it depicts. Nair is a director of actors and mise en scène, and her successes are measured in the depth and warmth of the worlds within her films, not in pyrotechnic visual trickery. In The Namesake, there is a tangibility of setting that outstrips all of her previous achievements. The Ganguli residence is relentlessly physical - a movie set, yes, but far more lived-in and real than most movie sets. This is vital to the effect of the film, a grand exploration of domesticity, in which all things lead back to home.

Family is a deeply clichéd topic for the movies, and so is the idea that foreign-born communities are a sort of extended family; but The Namesake is sufficiently loving in its representation as to make those clichés easier to stomach. The world decidedly does not need any more films about the immigrant experience of America - a genre that has been exceptionally well-explored by everyone from Martin Scorsese to the schmuck who made My Big Fat Greek Wedding - but somehow, Nair's enthusiasm for the world of her film, and the extraordinary skill with which it has been carried off, manage to convince me that this one time, it's okay to have another one of the goddamn things.

Compressing 25 years and the entirety of the immigrant experience into two hours is a daunting thing to do, and Nair and her frequent collaborator, screenwriter Sooni Taraporevala attack the problem with some particular innovation. The word "elliptical" has become heavily overused to describe films in the last couple of years, but I can't think of another word for The Namesake, which comprises five years into a single cut, while following a few days for many uninterrupted minutes. It's a challenging way to structure a narrative, but it adds to the film's overall effect of hazy memories and lost time. The back-and-forth of the story is almost like an alternating series of deep and shallow breaths, the film's way of gathering oxygen for the places it matters most (disclosure: I haven't read the novel by Jhumpa Lahiri that the film is based on, and I'm not likely to, so I don't know if it has the same elliptical structure).

So that's what the film does well: capturing a precise space, and capturing the way that time is slippery and can't be captured. Now it's time for what the film doesn't do well, which is remain not hideously boring.

False endings are a dangerous, deadly thing that kills the strongest narrative. The Namesake has, by my count, three. And the first of these isn't just a momentum-killer: it's the legitimate end of the film, the place where all of the arcs have closure and the emotional conflict that drives the plot up to that point is over. But that would make the film just about a single family, and of course the point is to be the great Bengali-American story (which I'm theoretically okay with), so the last quarter of the film - a full quarter! - is dedicated to what amounts to a great huge epilogue that introduces strands just to have something to tie up. It's much like the last hour of The Return of the King, or to keep things in the realm of epics about South Asian families, it's much like World of Apu, the third film in Satyajit Ray's Apu Trilogy, in which the great dramatic arc that covers the first two films has resoundingly ended, and the entire film is just a needless parenthesis.

It doesn't help matters a tiny bit that this is also the point where Kal Penn steps up from being an ensemble member to the dramatic hub of the story, and this is more than he can handle. When Gogol is a simple character with the shallow dreams of a suburban youth, Penn is great. When he becomes a deeply conflicted adult, Penn is not as great, and much, much worse than the great Khan and Tabu, whom he begins to replace. It's extremely difficult to stay emotionally invested, and the film up to now has been a master class in emotional investment.

But with or without a draggy fourth act, the film is a success, especially for the time of year, and it has an honest humanism that's much more satisfying than the cookie-cutter variety that tends to mark American films about families. A masterpiece? No, but it doesn't really have to be.