Detective Tom Welles (Nicolas Cage) is in over his head. He has been hired by a rich widow (Myra Carter) who has discovered what she believes to be a snuff film in her late husband's belongings. Upset over the atrocity, she wants Detective Welles to ascertain whether the film is authentic or merely a disturbing hoax.
Stumbling upon one incredulously lucky break after another, Welles follows the trail to Hollywood. There, he meets up with Max California (Joaquin Phoenix), an adult bookstore clerk who takes him on a tour of the seamy world of illegal pornography.
As the depravities Welles encounters get worse and worse, his case turns into a personal quest. He needs to understand the pivotal question: why? Why is pure evil allowed to exist? But will understanding the answer to that question cost him his own sanity?
Many of the conclusions drawn by 8MM were also made by screenwriter Andrew Kevin Walker's superior 1995 effort, Seven. However, not only does 8MM lack the earlier film's strong characterizations and sense of structure, but 8MM director Joel Schumacher isn't able to create a visual style anywhere near comparison.
Nicolas Cage has the misfortune to play an everyman character whose most sympathetic trait is the fact that, well, he's being played by Nic Cage. He is never able to connect with the audience, even though he is intended to be their guide to the underworld.
Joaquin Phoenix' Max California at least has a few character quirks that he can play upon, whereas Cage is given only one (he pretends he doesn't smoke, although he does). But, then again, Phoenix exists primarily as a way to take the movie deeper and deeper into the world of porn. (Though it works structurally, it doesn't really make much sense in the movie. Since Detective Welles is looking for some highly illegal stuff, why doesn't he simply start with the bottom dwellers instead of working his way down?)
8MM is the type of movie that, though not particularly poorly made, makes you seriously wonder, "why am I watching this?" It's not merely that the movie is depressing and/or sordid (though it is). But there has to be something that engages you among the depressive sordidness... and that crucial part is missing from 8MM.