Richard Jenkins stars in "The Visitor."

Sometimes a coincidence is not just a coincidence, and a chance meeting is not something that should be brushed off easily.

In Tom McCarthy’s ("The Station Agent") "The Visitor," the fickle winds of fate draw together two men from vastly different worlds, who will forever change each other’s lives. Like such movies as "Magnolia" and "Nashville," it’s a drama about overlapping fates and unexpected epiphanies. It’s a movie about how luck and chance can change you forever.

It’s also a movie about the big city, and about a staple of the modern urban lifestyle: the illegal sublet. Richard Jenkins plays an upper class Connecticut professor who visits New York City one day to present an academic paper. Traveling down one evening to the Big Apple for the first time in years, he returns to the Manhattan apartment he has not been to in years, since before his wife died. And walking into his downtown flat, he is stunned to find two illegal squatters who have taken up residence, two illegal immigrants who had been told that it was an apartment available for rent.

Initially throwing them out, the soft-hearted professor eventually takes them back in, quickly becoming their friends and rushing to their aid when one is arrested by the New York police and thrown into a remote detention center to await deportation.

It’s here where an unlikely man finds himself in an unusual position, and takes the story in unexpected directions. What had been a movie about chance encounters in the big city turns instead to one American citizen trying to understand the complicated maze that is the nation’s immigration system. Finding himself visiting detention centers, consulting with immigration attorneys and forced to confront anti-immigration sentiment face to face, "The Visitor" emerges not just as a sweet story of friends, or smart story of a raging political issue, but also a sad story about broken hearts and shattered dreams.

Dealing with such a provocative issue, "The Visitor" could have easily become a polemical device - propaganda for one side of the illegal immigration issue. But it doesn’t thanks to the vulnerability and the tenacity of Jenkins. Here’s an actor that so many audiences know, from previous supporting roles, who here steps up to the plate in the lead role, playing a man who is lonely since the death of his wife, shy in his ability to reach out beyond himself, who is galvanized here into action because of a short, but strong friendship that he refuses to turn his back on.

For that matter, here’s the kind of movie that grows and unfolds in ways that you couldn’t expect, who wins you over with its heart before leading you to debate your own beliefs, and reconsider your outlook on the world. It’s a lullaby of a film, a sweet love letter to a city, and the personalities that reside within.

It’s one of the best films of the year.