For those who fell behind (or never started), both previous seasons of “A.P. Bio” are available on Peacock, and both are absolutely worth watching. Glenn Howerton plays Jack, a former Harvard philosophy scholar who loses out on his Ivy League dream job and has to return home to teach high school biology. Understandably frustrated yet irrationally vengeful, Jack has always sported an edge ideally suited for dark-but-not-too-dark comedy. If you find pranks to be childish (no matter how elaborate) or revenge a dish best ignored, perhaps “A.P. Bio” isn’t for you. But watching Jack’s sharp edges get sanded down by a great group of teen actors as well as perfectly cast supporting players is an otherwise ideal binge.

Season 3 keeps the cutting wit and comic timing of the past and combines it with a renewed episodic focus. “Tiny Problems” sees the Season 3 MVP — Paula Pell’s wacky secretary Helen — enrolled in Jack’s class, and writer Donick Cary finds unexpected ways to maximize her disruptive presence. (Pell’s excellent physical comedy is second only to Helen’s magnificently creaky voice.) “That That That” pivots to a “Shining”-inspired haunted house story, as Jack’s guilty subconscious drives him mad while trying to record an audition for another school. (Howerton has always been willing to put himself through the wringer for a laugh, whether he’s covered in spaghetti or screaming at full volume, but the way he contrasts such extremes with subtle moments of comedy is what really makes every effort connect.) But “A.P. Bio” hits its peak in “Gary Meets Dave,” an episode where the first 10 minutes introduce the plot through fake “Previously on ‘A.P. Bio’…” segments (don’t worry — you didn’t miss an episode), and the last five wrap things up through similarly efficient “Next on…” scenes. Principal Durbin (Patton Oswalt) and Helen try to raise money for the school’s dying ram mascot; the teachers — Stef (Lyric Lewis), Mary (Mary Sohn), and Jean (Michelle Jones), a delightful trio —  host an unapproved mall-walking group in the school; Jack hunts for a bird, and the kids get in over their heads with a purported drug dealer. Dan Schofield’s script creates propulsive comedy by eliminating transitions and building suspense as to how these slightly overlapping stories will collide, and when they do, it’s a huge payoff.

“A.P. Bio” may not be the next great comedy. Hell, it might not survive past this season. But Season 3 proves it’s one of the most fundamentally sound sitcoms out there. From the performances (really, those kids are good!) to the direction to the writing to the ethereal collective chemistry that stems from great character-building, every layer is so well-executed that even for the few off episodes, there’s still plenty of laughs to be had. Right now, with the new season in my rearview, I wish there were 50 more episodes of “A.P. Bio” to enjoy, and isn’t that the true measure of a sitcom? The compulsion to go back? So savor Season 3, or the whole series. This hard worker definitely earned its “A.”

Grade: A-

“A.P. Bio” Season 3 premieres all eight episodes Thursday, September 3 on Peacock. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.