Yesterday I watched what has instantly become one of my favorite films of the year: “Zodiac,” about the search for the Zodiac killer in 1970s San Francisco.

I’d heard a little bit about the movie when it came out early in the spring, and it seemed like something I’d want to see, and then I promptly forgot about it. But in the past few days it’s appeared on several critics’ end-of-year best movies lists, so I decided to rent it from Netflix. I popped it into the DVD player and got sucked right in.

I can’t explain exactly why I enjoyed it so much. It just had this haunting effect on me. It’s too long (2 hours 38 minutes), and yet the length is just right for the story David Fincher is trying to tell. I haven’t read much background about the film, but Fincher (who also directed “Se7en,” “The Game,” “Panic Room,” and “Fight Club”) seems as obsessed with the story as Jake Gyllenhaal’s character, Robert Graysmith, is with solving the murders.

The movie has a great cast. Jake Gyllenhaal, Mark Ruffalo, Robert Downey, Jr. (who deserves an Oscar nomination for Best Supporting Actor, in my opinion), Anthony Edwards, Dermot Mulroney, Philip Baker Hall, Brian Cox, Chloe Sevigny, even Clea Duvall in a very small role. Familiar faces keep popping up all over the place.

Best of all is the eerie score by David Shire, which I’ve downloaded and am listening to as I write this. I think it’s the music that really makes the movie for me.

It turns out that a two-disc edition, including a director’s cut, comes out in just over a week. I’ll definitely be buying or renting it.