BoJack Horseman (voiced by Will Arnett) in Netflix’s “BoJack Horseman.” (Netflix)

How did a story about a depressed, alcoholic horse become one of the most human shows on TV?

A few years ago, you couldn’t get me to watch an episode of Netflix’s “BoJack Horseman.” I wrote it off as just another adult cartoon and assumed it wouldn’t be worth my time. With apologies to Seth MacFarlane, I’d probably logged a few too many episodes of “Family Guy.”

But “BoJack Horseman” isn’t just another adult cartoon. It’s a smart, often tender comedy that puts a spotlight on the realities of addiction and mental illness, while skewering celebrity culture and serving up some of the best cameos (Margo Martindale as “character actress Margo Martindale,” anyone?) on TV.

The fourth season arrives Friday on Netflix, with BoJack (voiced by Will Arnett) more depressed than ever following the death of his “Horsin’ Around” co-star Sarah Lynn, who overdosed during a co-dependent bender with BoJack. Racked with guilt, BoJack left his Hollywoo mansion, driving aimlessly and recklessly away from a life spent in the shadows of fame.

“BoJack Horseman” takes a somewhat risky swerve in this season’s first episode, as its title character is nowhere to be found. This leaves us spending more time at the home of BoJack’s friend/ghostwriter Diane Nguyen (Alison Brie) and her dim but lovable husband, Mr. Peanutbutter (Paul F. Tompkins), who happens to be running for governor of California. (Can “BoJack Horseman” pull off a fracking story line? You betcha.)


Mr. Peanutbutter (voiced by Paul F. Tompkins), who’s running for governor in California. (Netflix)

When we finally do catch up with BoJack, he takes a detour that brings his past into harsh focus. Through flashbacks, we learn more about his family — specifically his caustic mother, Beatrice (Wendie Malick), whose own childhood provides some insight into the way BoJack was raised. Beatrice also makes appearances in the present that capture the challenges of confronting childhood resentment with an aging parent.

BoJack’s thorough family history gives necessary context to Hollywoo’s newest arrival — an adopted teenage girl named Hollyhock (Aparna Nancherla), who shows up wanting to know more about the famous actor people have always said she resembles. Eagle-eyed viewers will realize they have seen her before. Cue the fan theories!


Hollywoo’s mysterious new arrival, Hollyhock (voiced by Aparna Nancherla). (Netflix)

No matter how grim “BoJack Horseman” gets, the show always manages to uplift with a shrewd cameo (this season’s highlights include Vincent D’Onofrio and Felicity Huffman) or wacky subplot. And “BoJack Horseman” never neglects to expand its rich, Hollywood-parallel universe, which is largely responsible for the show’s sardonic brand of humor.

In a sort-of bottle episode, Mr. Peanutbutter’s gubernatorial fundraiser goes off the rails in spectacularly West Coast fashion, trapping a mix of actors, screenwriters and other Hollywood types — of both the human and animal variety — in close quarters. “I have no original ideas, I just repeat things I hear,” a parrot in formalwear says when things start to go south. “I’ve never been in love,” a fellow partygoer confesses. “I’ve never been in love,” the parrot squawks.

Season 4 also expands the stories of those in BoJack’s inner circle. Diane and Mr. Peanutbutter navigate their marital issues in a shocking way, made all the more absurd by the fact that one of them is a labrador retriever. BoJack’s couch-surfing friend Todd (Aaron Paul), a perpetual, unwitting object of Hollywood obsession, finds himself in a relationship with an actress in need of some image rehab.


Princess Carolyn (voiced by Amy Sedaris) takes the lead in what might be the season’s most adventurous episode. (Netflix)

But the most welcome screen time goes to BoJack’s ex-girlfriend/former agent Princess Carolyn. The pink Persian cat (voiced by Amy Sedaris) takes the lead in what might be the season’s most adventurous episode, which imagines her great-great-great granddaughter giving a class presentation about a pivotal day in her ancestor’s life.

It’s a moving and unexpected installment that rivals last season’s standout “Fish Out of Water,” about an underwater film festival, and represents what “BoJack Horseman” does best. It offers hope but never ignores the sorrows that are inevitable in real life. So what if that life happens to be animated and surreal? In a way, that just makes it easier to watch.

An earlier version of this review incorrectly referred to Mr. Peanutbutter as a golden retriever. He is a yellow labrador retriever.

BoJack Horseman (12 episodes) returns Friday on Netflix.