Beautifully rendered, classic story, densely plotted, and faithful to the original adaptation, by all means “Watchment” is a triumph in almost every sense of the word.

So why do am I left feeling like something is missing?

The plot has been bandied about, so I’ll be as brief as possible in recounting: it’s some sort of alternate 1985, where costumed heroes once the glamorous existence most celebrities do, but have now been banned by President Richard Nixon (he slipped through a ban on term limits and remains for an indefinite number of terms). The Cold War is white hot, and nuclear war is expected any day now.

One of two remaining legally-active heroes, The Comedian (Jeffrey Dean Morgan) is murdered, and the vigilante Rorschach (Jackie Earle Haley) suspect someone is knocking off “masks.”

The film is a delicately-constructed mash of the individual stories of each hero, explaining in a sense why each decided to become a hero and the resulting consequences of their actions. Most are retired, some in secret, some publicly, but none happily.

As you can see, my “brief” synopsis of the film encompasses three paragraphs, which should indicate that this isn’t your typical good-guys-vs.-bad-guys superhero yarn. It’s dark, violently and sexually graphic, and carries a decidedly bleak outlook. This ain’t Spider-Man.

The acting is a little scattershot; I was particularly worried about the handsome Patrick Wilson taking on the role of the mousy Dan Dreiberg/Nite Owl, but he was just fine.

Malin Ackerman as Silk Spectre (II) is a little less impressive, as she stumbles through some of her lines, but it’s Jackie Earle Haley’s turn as Rorschach that really amps up the film. He is spot on, intense and vicious, but with just enough of a sentimental streak to keep him honest on some level.

So why am I feeling just a touch glum about the whole thing?

I’ve had the “Watchmen” graphic novel sitting on my shelf collecting dust for I think 5 years or so. I bought it for a college course on comics that I dropped mid-semester for scheduling purposes and never gave it a second look, until about three weeks ago. I poured through the book, was sucked in, transfixed, and enchanted.

Before the book’s climax, I considered waiting to let the movie resolve the story, but gave into temptation and finished it.

Then I watched the DVD “Motion Comic” that is basically a 5-hour DVD version of the book, complete with panels and dialog bubbles, but narrated.

By the time I got to the theater, there was no mystery left for me. Most of you who’ve read my reviews and posts over the years know I’m a low-level comic geek, but I wasn’t in the “Watchmen” crowd growing up.

In that way I was disadvantaged, but I can’t help but think my crash course took some of the magic out of the cinematic experience. I found myself mentally checking off the major plot points and pondering what didn’t make it rather than enjoying what was there.

So my ultimate advice: if you’re a hardcore who knows the novel inside and out, you’re seeing this and will have a strong opinion on it one way or the other.

If you’re considering buying a ticket to “Watchmen” and don’t know the novel, before you go, buy a copy of the book, see the movie, then go home and start reading.

Half the fun of this film is picking at the nuances and the changes and which works better, but if you’re a newbie, don’t let that ruin the film experience.