Mary Poppins Returns, ★★★ , Opening Wednesday, Dec. 19

Emily Blunt is pleasantly prim and proper in Mary Poppins Returns. She cuts a nostalgic figure, capturing the wit, whimsy, and elocution of the eponymous nanny, from her parrot-head umbrella to her clipped spit-spots and pish-poshes. Blunt doesn’t have Julie Andrews’s vocal chops, but she can carry a tune.

Pleasant and nostalgic are the watchwords of director Rob Marshall’s gauzy, inconsequential sequel, which again revolves around Mary Poppins being a delightful deus ex machina who arrives to save the strained relationship between a fussy Banks patriarch and his moppets. This time, it’s Michael Banks (Ben Whishaw), all grown up and the father of three children. In lieu of Dick Van Dyke’s cockney chimney sweep, Bert, we get Lin-Manuel Miranda’s cockney lamplighter, Jack—Bert’s former apprentice, we’re told. As her mom was once a suffragist, the adult Jane Banks (Emily Mortimer) is a labor organizer. Ellen (Julie Walters) is still the housekeeper, and Admiral Boom (David Warner) is still blasting his rooftop cannon.

The film announces that it’s set during The Great Slump (a few decades after the original Mary Poppins), but there’s little sign of widespread economic distress. Although the Fidelity Fiduciary Bank, apparently flush with tuppence, is foreclosing on the Banks home, that’s because of Michael’s blunder. Michael, a recent widower, works at the bank, whose president (Colin Firth) is secretly thwarting his attempts to get his house out of hock before Big Ben strikes midnight on Friday.

Even the musical sequences follow a derivative formula. Like the original film, Mary Poppins and the Banks children enter a cartoon universe, one of the new movie’s standout scenes. Jack and his fellow lamplighters have a song-and-dance number called “Trip a Little Light Fantastic,” this film’s version of “Chim Chim Cher-ee.” One departure is “Turning Turtle,” led by Meryl Streep as Poppins’s Eastern European cousin, the proprietor of a topsy-turvy fix-it shop. The segment is lively, but it’s also utterly untethered from the narrative. While the Mary Poppins soundtrack gave us about half a dozen Sherman Brothers classics that remain indelible in pop culture, Mary Poppins Returns has several enjoyable toe-tappers you won’t readily recall tomorrow.

Miranda is a gifted musical performer who has a few show-stopping moments, but his acting is otherwise inert. He and Blunt exude minimal chemistry, and a flirtation between Jack and Jane is a half-baked subplot that goes nowhere. Indeed, the main cast is so reverential and referential that their performances feel trapped in amber. It’s both delightful and problematic when the film seems to spring to life only during one-offs by Streep, Angela Lansbury, and, yes, Dick Van Dyke (not reprising his role as Bert, however).

After five decades, it’s a joy to finally revisit the world of Mary Poppins. But like a spoonful of sugar, the heady rush soon gives way to a comedown that leaves you craving something more satisfying.