Ben Sinclair in “High Maintenance.” (David Russell/David Russell)

Some terrible, earthshaking event has occurred in the wider world of “the Guy,” the superchill but always reliable Brooklyn pot dealer (played by Ben Sinclair) who anchors HBO’s subtly brilliant dramedy “High Maintenance,” which returns for a longer and even better season Friday.

Everyone, including the Guy, receives the breaking news on their phones, jaws agape, curse words flying. It’s so awful that the show cleverly declines to name it — bad enough to require candlelight vigils and quiet subway commutes. Is it another 9/11? A mass shooting bigger than all the rest? Is it the surprise outcome of a national election? “What Now?” asks a somber tabloid headline.

Whatever it is, it sets the Guy’s phone ablaze with urgent texts from his many customers, all seeking the immediate relief of cannabis. He sets off on his bike with ample supplies of Northern Lights and Amnesia Haze and other weed varietals, vape pens and rolling papers in a small lockbox he carries in a backpack.

“High Maintenance” is only ostensibly about marijuana, and when it is, it is refreshingly past the old humor and high-jinks that used to accompany ’70s-style comedies about its sale and use. I just got back from a couple weeks in California, where, as of Jan. 1, it’s legal to purchase pot from legitimate stores for recreational use. But good luck with that — the TV and newspapers were so full of ifs-ands-or-buts about how and where to buy it (to say nothing of the faraway threats of U.S. Attorney General Jeff Sessions, et al.) that you might as well just stick with your own Guy for the time being. If you have a Guy, that is.

“High Maintenance” has something to tell us about the banal normalcy of the drug in the 21st century, particularly in big cities, far away from the opioid crisis in flyover states. Created first as a Web series in 2012 by Sinclair and Katja Blichfeld, the show uses the Guy as the common thread that connects a breathtakingly diverse array of customers — diverse not only in the usual compartments of age, race, gender and sexuality, but diverse also in their present state of mind. It’s about as close as a show can get to a documentary feeling without actually being a documentary. For people who are interested in other people, “High Maintenance” is like finding a small treasure.

Sometimes the Guy barely makes a cameo, just a quick delivery. This season’s stories feature, among others, Orthodox Jews ostracized from their families; a young man who is eager to share news of his latest weight loss, which seems entirely inappropriate given the unnamed disaster (“Apocalypse wow!” he types out with a photo of himself, then reconsiders); a woman having a three-way romp with two men in a hotel room, oblivious to the breaking news (and to the men’s relationship to one another); a couple visiting their adult daughter, who has set them up in an undesirable Airbnb rental; a real estate broker who dreams of buying her own place; a young couple who jump at the chance to leave their cooperative group house to move into a nice, city-subsidized apartment — only to realize they’re living in a condominium caste system where tenants in more expensive units have special access to high-end amenities.

It’s the New York that we usually get only fleeting glimpses of, in shows like “Girls,” since television still sticks so emphatically to imaging a fantasy New York that’s hardly there anymore — if it ever was. “High Maintenance” has a way of making New York look sufficiently difficult, emotionally draining and intensely personal. Yet, despite the show’s preference for the more melancholy aspects of someone’s day, it retains hope in fleeting moments of happiness, not all of which are laced with THC.

Once in a while, “High Maintenance” lets us know a little more about the Guy himself. An episode this season lands him in the hospital after a bike spill. Waiting endlessly for a surgeon to look at his broken left arm, the Guy acquiesces to an IV drip of Big Pharma’s best painkillers, with trippy results.

“High Maintenance” is hardly an advertisement for pot; once in a while it even seems to suggest that the drug keeps the Guy and his customers in a slightly numbed state of response to the world around them. These are not the stereotypical stoners of yore. Like so many Americans, they’re just looking for a break from all this. That they do and don’t find relief is part of what makes the show so believably, wistfully good.

High Maintenance (30 minutes) returns Friday at 11 p.m. on HBO.