A very rich man has died and a suspicious film has been found in his secret vault. A film which, if genuine, would be the first snuff film ever in the world! However, the footage is murky and could be fake. It would require an investigator of the first order to crack this case.
If there is one thing Nicholas Cage is good at, it's beating up women on bee-infested islands. If there are two things he is good at, then investigating snuff films is probably number two. And so with Nicholas "a snuff's enough" Cage on the case, our movie begins.
The premise is cool- urban legends are scary and snuff films are possibly the greatest urban legend of them all (except for the hook murderer one). The only way to improve on that would be to get Nicholas Cage involved, and they've already done that. Unfortunately, they then went on to find the only thing that could ruin it and did that. So while the movie starts out pretty strong eventually it just becomes a string of increasingly unlikely coincidences until you get to the end (which features a dramatic battle in the rain, like most private investigations).
So this is what you are up against when you sit down to watch 8mm. It's one of those movies where the hero will watch a ten second clip and find a shadow of a guy in a single frame and then track that guy down and it just so happens that the first place he shows up at is behind the entire thing.
However, the cool premise and dark photography makes it worth putting up with that.