In “The Baby-Sitters Club,” the charming Netflix adaptation of Ann M. Martin’s wildly popular children’s book series, there’s a witch. Not the cauldron-stirring, spell-casting sort of witch. This isn’t that kind of kids’ adventure story.

Instead, Esme Porter (Karin Konoval) is a “spiritual practitioner” who hosts “share-a-monies” in suburban Stoneybrook, Conn. “Witch,” she says, is a name that’s come to be used for “people, primarily women, who refuse to conform to society’s expectations of who they should be.”

This makes a pretty good mission statement for the tween entrepreneurs of “The Baby-Sitters Club,” and for the show itself. It is in one sense exactly what the title says it is: a show about seventh-graders who start a babysitting business. But it also defies expectations, and exceeds them.

It’s a richly character-­based story about growing up, dealing with change, growing apart from and back together with friends. It’s sweet but not cloying, smart but not cynical, full-hearted and funny enough to please both grown readers of the original books and the young target audience of the new series — and even plenty of viewers (like me) who are neither.

Like the books, the 10-episode season, which arrived Friday, begins with “Kristy’s Great Idea,” in which Kristy Thomas (Sophie Grace) concocts her business idea when her mother, Elizabeth (Alicia Silverstone, repping the original generation of readers), is stymied finding last-minute child care.

Kristy, a steamroller of confidence, persuades her friends Mary-Anne Spier (Malia Baker) and Claudia Kishi (Momona Tamada) to start the club, which eventually adds new girls in town Stacey McGill (Shay Rudolph), an expat from the Upper West Side, and Dawn Schafer (Xochitl Gomez), a free spirit from California.

With the books as grounding — and a terrific, believable young cast — the series jumps out of the gate with a rich sense of the girls’ characters and the nuances of their relationships. The artistic Claudia has been distant from Kristy, partly because she’s developing different interests, partly because Kristy can be domineering. The introverted Mary-Anne worries that her friends are growing more sophisticated while she still dresses “like the world’s oldest toddler.”

Essentially, “The Baby-­Sitters Club” is a procedural, in which the cases involve not crimes but kids: a trio of tiny terrors, a delightfully morbid little girl who holds a mock funeral for her doll. On top of this are longer arcs, like Elizabeth’s engagement to jovial rich guy Watson Brewer (Mark Feuerstein), whom Kristy stubbornly resists welcoming into the family.

Showrunner Rachel Shukert (“GLOW”) and executive producer Lucia Aniello (“Broad City”), veterans of feminist comedies about friendship, have created a “Baby-Sitters Club” that’s a throwback in its optimism (and the vintage landline phone on which the club takes calls) but firmly rooted in 2020, from its multiracial casting to its storyline about cyberbullying to its girl-positive sense of humor. (When someone asks Claudia what her newest sculpture is about, she cheerfully answers, “Menstruation.”)

The empowerment themes of “Baby-Sitters” and its lightly worn sense of history are not there by accident. A 2016 New Yorker profile noted that Martin was influenced in creating the book series by her days as a student at Smith College during the fight over the Equal Rights Amendment.

That fight, of course, was dramatized this spring by “Mrs. America,” which built several individual episodes around members of the feminist coalition pushing for the ERA. “The Baby-Sitters Club” likewise rounds out its pint-size girl-bosses by centering installments around them and having them trade off the narration.

In one standout, Claudia uses her art to connect with her grandmother after her stroke, and unearths the story of her having been in a Japanese American internment camp. In another Mary-Anne, sheltered by her overprotective single father (Marc Evan Jackson), struggles with asserting herself. Babysitting gives her a voice, especially when she ends up looking after a trans girl, who she sticks up for when adults misgender her as “he.”

The characters learn to take care of themselves by taking care of others, exercising curiosity and patience. There are adversaries in “The Baby-­Sitters Club,” like a group of older teens who steal the girls’ business idea. But there aren’t really bad guys: not the packs of raging kids, not Kristy’s stepdad-to-be, not even a camp director literally named “Meany” (short for Philomena).

Instead, everyone has a story; everyone has decency that can be reached. What makes a good babysitter, it turns out, has a lot in common with what makes a good TV show: seeing even the most troublesome individuals not as problems to be overcome but as people with needs to be filled. “Behind every tantrum,” as Dawn sagely says, “There’s something else.”

It’s heartwarming but not heavy. That present moment that adults have created can be a bummer, but this piece of smartly reworked nostalgia is optimistic that future adults might do better and know better. As Esme puts it, “When children tell you something, believe them.”

“The Baby-Sitters Club” takes the witch’s lesson to heart, and the result is pretty magical.

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