Beginning in 2021, the ABC sitcom “Abbott Elementary” tells funny and heartwarming stories about the dedicated teachers at an underfunded Philadelphia school who work hard to inspire their students and create a better world.

Since 2005, the FX (and FXX) sitcom It’s Always Sunny in Philadelphia has…well, it’s told funny stories, too. Incendiary and raunchy funny. But is this comedy about egotistical, sleazy Philadelphia bar owners heartwarming? Hardly ever.

The cast of those two shows appeared together on Wednesday night in an episode of “Abbott Elementary” (available now on Hulu), teased by “Abbott” creator and star Quinta Brunson and “Sunny” creator and star Rob McElhenney The current TV season has started. When the crossover was announced, almost everyone who has ever watched these two shows wondered: Can this combination work?

The answer is a qualified “yes”. What Brunson and company have produced here feels like an “Abbott” episode with a version of the “Sunny” characters whose rougher edges have been sanded down, perhaps so that they don’t appear potentially harmful to schoolchildren.

This isn’t like when the “Mad About You” characters ventured into the similarly urban New York worlds of “Friends” and “Seinfeld,” or when Thomas Magnum and Jessica Fletcher appeared together in “Magnum PI” and “Murder, She.” “Abbott” and “Sunny” may share a city — and a corporate boss at Disney, which owns ABC and FX — but they don’t share a common sense of humor or purpose.

In the episode titled “Volunteers,” Abbott’s principal Ava Coleman (Janelle James) asks the community for help around the school. The gym scoreboard fell off the wall. The air ducts on the second floor do not distribute heat evenly. Raccoons destroy the community garden. Even the ever-optimistic and capable second grade teacher, Janine Teagues (Brunson), falls behind in grading. (“It takes a surprising amount of effort to give everyone an A for effort,” she chirps.)

Enter the gang from Paddy’s Pub: Mac (McElhenney), the goofy, boyish hunk; Charlie (Charlie Day), the uneducated, easily confused handyman; Frank (Danny DeVito), the millionaire and libertine; Dee (Kaitlin Olson), the selfish schemer; and Dee’s twin brother Dennis (Glenn Howerton), the handsome sociopath. True to their nature, the gang in “Sunny” doesn’t come to Abbott because its members actually want to do good; Rather, it is due to the court-ordered charitable work. (They were caught dumping 100 gallons of baby oil, 500 T-shirts and a Cybertruck into the Schuylkill River.)

The episode is structured a bit like a superhero comic book team-up, with characters from each series working together in various subplots. Ava designs the ever-helpful Mac as her personal assistant. Frank agrees to help first grader Gregory Eddie (Tyler James Williams) and school administrator Mr. Johnson (William Stanford Davis) in the garden. Dee—who, like Janine, attended the University of Pennsylvania—becomes a surprisingly adept second-grade classroom aide.

Meanwhile, Charlie answers a call from sixth-grader Jacob Hill (Chris Perfetti) to repair the plumbing. But Charlie’s inability to read worries Jacob and he hands Charlie over to teachers Barbara Howard (Sheryl Lee Ralph) and Melissa Schemmenti (Lisa Ann Walter) so they can take him to the library.

Dennis is conspicuously absent from all of these storylines. He appears at the beginning of the episode and then quickly disappears, wanting to avoid Abbott’s ever-present documentary cameras. (The sitcom falls into the “mockumentary” subgenre.)

It could be that Dennis’ entire personality in Sunny – as a proudly amoral and predatory womanizer – was simply too hard to rein in for such a family-friendly series. Otherwise, it’s surprising – and somewhat revealing – how well the “Sunny” characters fit in.

Frank’s general weirdness meshes well with the eccentricities of Mr. Johnson as they argue about how to outsmart the raccoons. (When he hears that Gregory plans to spread chili powder and garlic on the floor, Frank warns that it will “make the dirt taste delicious,” and then eats the dirt himself.) And while Dee initially has a sisterly bond with Janine, kills she tries to lighten the mood by repeatedly flirting with Gregory, Janine’s boyfriend.

None of this is too out of character for “Abbott,” where strange and annoying characters keep popping up and briefly making life difficult for the teachers. The two series also share the Philadelphia bond, evident in this episode in references to the UPenn hangout Smokey Joe’s and in a quick count of how many of these characters got into a fight at an Eagles game. (The answer: pretty much all of them.)

The relative seamlessness of this crossover may be due to the series’ less frequently discussed qualities: “Abbott” is often a little meaner than its reputation, and “Sunny” is sometimes unexpectedly sweet.

It’s no surprise that the “Abbott” character who is the most active (as opposed to reactive) in this episode is Ava, who has a tendency to be sneaky. The writers often lean on Ava when they need someone to hurl insults or do something dirty, and here she happily takes advantage of Mac, who’s hoping to impress the principal and go home early. Instead, Ava is looking for ways to keep the free workforce going longer.

It’s also no surprise that the “Abbott” writers are following the “Charlie learns to read” plot. Charlie is a weirdo. (When asked what kind of library books might interest him, he lists three of his favorite subjects: beer, “milk steak,” and bird law.) He’s also charmingly childlike in his own crazy way.

The fact that the two series fit together so well in the end is a testament to the talent of these actors, all of whom are capable of delivering laughs. Your next test? If the cast of “Abbott Elementary” appears on an episode of “It’s Always Sunny in Philadelphia” as planned for the upcoming season. We now know that the cast of Sunny can be quiet when they need to be. But how nervous can the “Abbott” cast get?