Paul Thomas Anderson’s Inherent Vice is sure to polarize and challenge the expectations from a film noir. It’s a woozy tapestry of gung-ho cops, mysterious drug lords, disaffected Flower Children, fringe political anarchists and lots of marijuana use by its lead private investigator, which only casts a wider sense of paranoia and murkiness around the whole affair.

It’s also about the tenuous moment in time when sunny California, as the template for America at large, changed from the Summer of Love into something decidedly more sinister. Now, full admission. I worship P.T. Anderson’s films, so take the rest of this with a cinematic grain of salt. Two of his most divisive films, Magnolia (1999) and The Master (2012), I consider as two of the best films of their respective decades.

Like those ambitious efforts, Inherent Vice doesn’t play by the rules. The dialogue and voice-over (by indie singer Joanna Newsom) evoke the guttural poetry of a Hunter S. Thompson novel. Scenes between characters run on for minutes at a time, often in a slow zoom single take, allowing the words and their hidden meanings to take shape before our eyes. The actual case taken on by “Doc” Sportello (Joaquin Phoenix) doesn’t congeal into an easily explainable finale, often raising more questions than it answers. Inherent Vice isn’t a disposable Friday night date film. It requires patience, a bit of personal interaction and the desire to lose oneself in the convoluted universe Anderson and novelist Thomas Pynchon, whose book the film is based upon, have created. It’s a tall order but one that delivers on its majestic intent.

Taking place in the fictionalized ocean side town of Gordita Beach, California, in 1970, private investigator Larry “Doc” Sportello (Phoenix) has his nightly “decompression” time interrupted by ex-girlfriend Shasta Fay (Katherine Waterston) asking for help. She’s involved with some bad people who want to capitalize on the fortunes of her current boyfriend, wealthy land developer Mickey Wolfmann (Eric Roberts). He accepts the assignment and, before long, finds himself in a cascading tunnel of police investigations, shady characters and loose ends, all the while continuing to smoke pot which most assuredly obfuscates his own thinking on the case.

In addition to all that, other people begin seeking him out for the resolution of their own missing people. A distraught housewife (Jean Malone) wants “Doc” to find her missing jazz saxophonist husband (Owen Wilson). A Black Panther member (Michael K. Williams) enlists “Doc” to investigate an old cellmate with ties to the Aryan Brotherhood. His visit to a massage parlor and its kinky employee (Hong Chau) exposes “Doc” to the Golden Fang — which could either be a nondescript boat or the corporate name for a vertical drug smuggling operation responsible for pummeling the West Coast with heroin.

Somehow, all these leads inadvertently careen back to Wolfmann. Even the help of “Doc’s” supposed allies, including his lawyer buddy (Benecio del Toro), Deputy District Attorney/old girlfriend Penny (Reese Witherspoon), and overbearing Detective Bigfoot Bjornson (Josh Brolin), lead him further down the rabbit hole of suspicion, confusion and alienation.

Inherent Vice features so many red herrings, unusually zany cameos (Martin Short, incredible!) and diversions from the truth it soon becomes almost a parody of film noir. Fasten your seat belts. This isn’t your father’s Sam Spade.

In Anderson’s sophomore epic film on the travails of the porn industry, Boogie Nights (1997), the central set-piece involved a New Year’s Eve party on December 31, 1979, where emotions boil to the surface and a violent outburst shatters the good times. Nothing’s the same after that. The 1980s arrived and video cassette effectively curtailed that industry’s heyday. Within that 20-minute set-piece, Anderson effectively conveyed the end of an era.

With Inherent Vice he stretches the collision of the old 1960s free love with the harsher realities of the 70s over two and a half hours. The Sharon Tate murders are mentioned. The horrible, degenerative effect of heroin on the body are alluded to several times. As Shasta Fay, actress Waterston is given a long monologue that succinctly delineates her feelings on the state of modern relationships.

Effectively, Inherent Vice is a very sad film behind its very comedic heart. Its narrative may not always make complete sense, but the mood it resonates makes all the sense in the world. It’s one of the very best films of the year.