Inherent Vice should probably be seen twice—the first time through, many viewers (including this one) will spend too much time trying to navigate the twists and turns of its sprawling, stoner-noir plot and miss the whole point.

It begins simply enough, as many great detective stories do, with a dame. Hippie detective Doc Sportello (Joaquin Phoenix) is mellowing out in his SoCal apartment when an ex-flame, Shasta Fay Hepworth (Katherine Waterston), wanders in to ask for his help in getting out of some shady affairs. Sportello takes the case pro bono, mostly so he can stay involved in Hepworth’s life. But he gets more than he bargained for, and so does the audience. The case is a darkly comic adventure through the convoluted counterculture landscape of Los Angeles in the post-hippie era.

Consider the exhaustive cast of characters: There’s the hippie-hating cop (Josh Brolin) who moonlights as a Hollywood extra and shares a contentious but mutually beneficial relationship with Sportello; an ex-junkie mom (Jena Malone) trying to go straight while looking for her husband (Owen Wilson), who may have faked his own death; a debauched dentist (Martin Short) with a penchant for cocaine and young girls; and a straitlaced district attorney’s assistant (Reese Witherspoon) who harbors a soft spot for freaks. There are Black Panthers and Nazis, real estate developers and drug dealers, and the pervasive feeling that they might all be on the same side.

Of course, that could just be the drugs talking. Writer-director Paul Thomas Anderson keeps the viewer closely aligned to the perspective of his perpetually baked protagonist. Sportello can’t keep the strands together (the foggy observations he writes down in his notepad provide the film’s biggest laughs), so neither can we. Some viewers will need a second viewing to stop trying to follow the plot and enjoy the film on its proper level, as an evocative and hilarious series of loosely-related vignettes about the moment America went dark.

It has become a career motif for Anderson, who’s recently cast his critical gaze on other key moments in American history: the oil boom of the late 19th century (There Will Be Blood) and the tidy post-war era (The Master). In Inherent Vice, it’s the moment that Hunter S. Thompson wrote about—“the place where the wave finally broke and rolled back”—when Charles Manson and the Zodiac killers gave the squares an excuse to crack down on the counterculture. In the confusing moral landscape of Inherent Vice, Anderson clearly sees the seeds of some of our contemporary social ills.

But such a description belies the fact that it is easily Anderson’s funniest film to date. It feels fitting when supporting characters greet Sportello with a casual “What’s up, Doc?” Like a Looney Tunes cartoon, Inherent Vice contains plenty of pratfalls and sight gags, and a protagonist who’s perpetually one step behind his prey, even if it’s never quite clear who he’s chasing.

Inherent Vice opens Jan. 9 at E Street Cinema and AFI Silver.