This is an exceptional movie. The budget was clearly less than monumental and there were no bankable stars. It belongs to no genre so there is no base to appeal to. The sex is subdued and there is little violence. No computer-generated images. I wonder who had the huevos to greenlight this. Somehow I doubt it would ever be made today.

Anthony Perkins is a young man who has just been released from a psychiatric facility, having accidentally burned his aunt to death when he set fire to the house years earlier. John Randolph is his sympathetic but skeptical parole officer. Perkins sets up residence in the town of Winslow, Massachusetts, evocatively photographed by David Quaid in a flat, TV style. You get to know Winslow -- the chemical factory, the river that purls through the town, the modest working-class home that Tuesday Weld lives in with her mother.

Weld is the champion member of the high-school band, and what a succulent piece she is, with her lustrous blond hair, her voracious and toothy grin, her unimpeachable figure. She bumps into Perkins at a hot dog stand. Perkins is a fabulist, maybe a trait he picked up in the funny farm, and he sweeps Weld up in his narrative.

Perkins pretends to be a secret agent from the CIA, keeping an eye on the chemical plant where he now has a job. They may be polluting the river. It's his job to find out if they're poisoning the water. "In a few years there may be nothing but monster fish between here and New York." One should not believe that the pollution is a symptom of Perkins' derangement. In 1968, there were virtually no laws governing the process. The film illustrates this lack of concern when the owner of the hot dog stand dumps his garbage in the river, then stops to wipe some mud spatters from his motorcycle. Two kids in New York caught cholera, of all things, from eating a watermelon they'd found floating in the Hudson. In any case, Weld is thrilled. She's eager to help him and wants to be a deputy secret agent.

The plot gets complicated and twirled around but not to the extent that we can't follow it. If, at first, Perkins is the fake and Weld is the naif, it gradually becomes clear that it's the other way round. I don't want to give away too much of the plot.

I attribute the success of the movie mostly to Lorenzo Semple's screenplay, which is full of oddments and stylishness. Noel Black's direction is functional -- not more than that -- but the story becomes so gripping that one's attention never drifts. Semple was also responsible for the outré and equally paranoid "The Parallax View." After "Psycho," poor Anthony Perkins seemed consigned to the role of not just maniac, but maniac being taken by thyrotoxic storm. Jerky and twitching and stuttering. Here he's merely given to excess fantasizing but is otherwise intelligent and, well, normal. Smart, maybe, but he doesn't know much about women, and he's abrasive towards his dumb superiors.

Perkins' and Weld's roles are pretty complex. They both handle the complexity well. Perkins must change from being slyly but playfully conspiratorial to being aghast. Weld has to morph from a gullible teen ager into a calculating young woman thoroughly committed to pursuit of hypothetical imperatives.

It all comes together quite well and I applaud everyone involved. Wish there were more like it today instead of all those trumpeting mastodons and monsters thumping their way across the megascreens.