“This outlandish buffoonery is beneath the office of the Governor,” the governor of California declares in the season-four premiere of “BoJack Horseman.” The buffoonery in question is Mr. Peanutbutter’s (Paul F. Tompkins) plan to win the race for governor in a literal race — a death-defying ski run down Devil’s Mountain. The premiere, “See Mr. Peanutbutter Run,” is a return to the silliness and clever humor that makes the show so laugh-out-loud funny. Watching Mr. Peanutbutter attempt to run for governor by challenging his rival to a ski race, viewers might be forgiven for thinking the new season would be more optimistic and upbeat than previous ones. However, true “BoJack” fans know the show is as much about its protagonist’s struggles with addiction, mental illness and self-loathing as it is about endlessly entertaining puns on the half-animal, half-human characters populating the show’s universe. That’s what makes “Bojack” so great — its ability to balance profoundly sad, compelling personal development with outlandish characters and plotlines. There’s no shortage of either this season — BoJack (Will Arnett) is forced to confront his aging mother and become a parental figure himself with the introduction of a new character, while Todd (Aaron Paul) trains a troupe of clown-dentists and dentist-clowns, resulting in predictable but hilarious hijinks. The plot of the latest season centers on the arrival of Hollyhock (Aparna Nancherla), a seventeen-year-old girl who BoJack discovers may be his daughter. Soon after she moves in, she convinces BoJack to bring his mother, Beatrice Horseman (Wendie Malick), back from her nursing home to live with them as well. Confronted by his abusive mother — who is now incapacitated by dementia — and fearing his own inability to parent, BoJack continues to drown his sorrows and push away those closest to him. The story builds to some of the most heart-wrenching scenes the show has offered — and those who have seen the previous seasons know that’s saying a lot. In flashbacks to Beatrice’s life throughout the season, viewers get a look into the generations of repressive, abusive parenting that resulted in BoJack’s state of near-constant misery, and, unsurprisingly, it’s not pretty. This season ups the emotional ante — these scenes are some of the most moving yet on “BoJack,” and that’s no small feat. BoJack’s deteriorating mental state has always been a central focus for the show, but this season exposes the depression and anxiety behind his tough-guy facade more than ever before. The outstanding sixth episode, aptly entitled “Stupid Piece of Sh—t,” is narrated by the anxious, self-hating voice in BoJack’s head. It’s disturbing to hear the constant stream of insecurities and insults BoJack’s consciousness throws at him, but even more so when Hollyhock reveals she hears that same voice in the back of her mind. In one of the most moving scenes of the season, BoJack falsely reassures her it’ll go away as she grows up. But BoJack is rarely so compassionate or helpful as a parent. Mostly, he just tries to avoid making the same mistakes his parents made, and his grandparents before them. And mostly, he fails. As viewers watch excruciating flashbacks showing how Beatrice’s parents instilled in her the self-hatred and insecurity BoJack lives with every day, they also watch BoJack — despite his very best efforts — pushing those insecurities onto the next generation. Hollyhock’s innocence and genuine love for BoJack make it all the more painful to watch. Things don’t look much better for the rest of the characters this season, either — Mr. Peanutbutter’s campaign drives a wedge between Diane (Alison Brie) and himself, Todd struggles with his identity after coming out as asexual and Princess Carolyn (Amy Sedaris) goes on a serious bender after a bad turn in her budding relationship with Ralph Stilton (Raúl Esparza). Of course, “BoJack” isn’t just a downer — its beauty lies in its ability to mix in quirky, clever humor with its overall deeply pessimistic outlook on life. There’s no shortage of silly shenanigans this season to provide some relief from the gloomy main storylines — one shining example is a running joke on the name of Princess Carolyn’s newest client, Courtney Portnoy (Sharon Horgan). Mr. Peanutbutter and Todd also stand out as bright spots in the bleak fourth season, with more of their trademark shenanigans. In the opening episode, Todd invents a “drone throne,” a drone with a hammock-like seat attached, only to promptly lose control in mid-air. “BoJack” is a rare show for taking on depression, anxiety and alcoholism in a truly meaningful way, while still tossing out hilarious tongue twisters about Courtney Portnoy left and right. The show is not afraid to tackle tough issues. It touches on fracking, sexual identity, mental illness, addiction — there’s even an episode that takes on the gender politics of gun rights. While it digs deeper into the profound sadness characterizing Bojack’s life, the show somehow never drops the ball on the fast-paced, clever humor that makes it one of the funniest on television today. That’s the triumph of “BoJack,” and this season delivers that magical combination just as beautifully as the first three, if not more so.