“Mary Poppins Returns” is 50 percent sequel, 50 percent reboot and 100 percent charming. This film offers a new story about the supercalifragilisticexpialidocious nanny, but the telling of it is heavily seasoned with nods to the 1964 original.

That tone is set right away when Emily Blunt — stepping into the title role that made Julie Andrews a star — makes her entrance, majestically drifting down out of the sky, not via her trademark parasol but hanging onto a kite. If the significance of that is lost on you, leave the movie immediately and go find one where stuff is being blown up every 90 seconds.

It took moxie for the filmmakers to even think about revisiting one of the most beloved family films since the invention of celluloid. This was an all-or-nothing proposition: They were either going to nail it or leave viewers drowning in disappointment.

Then again, it’s easy to have moxie when your team includes Blunt (a BAFTA nominee for “Girl on a Train”), Lin-Manuel Miranda (you’ve probably heard of the little Broadway show he created and starred in, “Hamilton”) and director Rob Marshall (who oversaw the Oscar-winning adaptation of “Chicago”).

It’s easy to have moxie when you’ve got established headliners like Meryl Streep, Julie Waters and Angela Lansbury so excited to be involved in the project that they signed on for minor roles.

And there’s no way you can’t have moxie when you’ve got Dick Van Dyke. The co-star of the original film, who turned 93 last week, turns up in a cameo in which he sings and dances and flashes the megawatt twinkle in his eye. Online dictionaries could link to that scene as the definition of “showstopper.”

The plot is not complicated — nor is it really the reason to see the show. The story takes place 25 years after the original. The Banks children, whom Mary took care of in the first movie — Michael (Ben Whishaw) and Jane (Emily Mortimer) — now are adults who face the prospect of losing the family home to a ruthless banker (Colin Firth, exquisitely channeling the saccharine yet duplicitous villains of Walt Disney’s 1960s-’70s family dramas).

Of course, there’s never even a nanosecond of doubt that Mary will find a way to save the day. Sorry if that’s a spoiler, but this is one of those movies in which the telling rather than the resolution is the joy. And there’s an abundance of joy.

Upon landing, Mary runs into an old friend, Jack (Miranda), who’s essentially the new version of Van Dyke’s character Bert. He’s a lamplighter, a profession that — as chance would have it — means he carries a long stick that he and his fellow lamplighters will use later to re-create the “Over the Rooftops” dance done in the first movie by broom-wielding chimney sweeps.

That’s far from the only production number that will look familiar. Mary and Jack dance with animated characters — hand-drawn in 2-D to echo a similar scene from the 1964 film. (The studio even brought back some of its retired animators to make sure they got the look right.)

Not everything is the same, however. There’s a computer-animated scene with dazzling visuals. And Blunt’s Mary has developed a taste for snark. When Michael muses aloud, “I had it all backwards,” Mary is quick to add: “A Banks family trait.”

Both Blunt and Miranda are marvelous actors, singers and dancers. But their most amazing feat is getting us to bond with these characters without making us feel we’re deserting the beloved ones created by Andrews and Van Dyke. This is not a replacement for the original film, but a delightful adjunct to it. Youngsters encountering Mary Poppins for the first time can enjoy her just as much as their parents did.

Mary Poppins Returns
⋆⋆⋆⋆ out of four stars
Rating: PG for mild thematic elements and brief action.