The glistening sunshine pop stylings of Swedish music group ABBA run far and wide, having inspired a long-running, Tony-nominated Broadway musical, a big-screen adaptation (2008's frequently-shark-jumping-but-who-cares-because-it's-so-dang-infectious "Mamma Mia!"), and now a ten-years-later film sequel. "Mamma Mia! Here We Go Again" is even thinner than its already-slight predecessor, a veritable cotton-candy clothesline upon which to hang a huge ensemble and an array of musical numbers, this time a mix of beloved hit singles and worthy but less well-known B-sides. Writer-director Ol Parker (2006's "Imagine Me & You") brings undoubted showmanship to his performance set-pieces, but also an underlying melancholic tone to a script touching upon the ever-fluid passage of time. The lack of substantive conflict, however, is certainly felt here, leaving one less engaged in between the sweet and rollicking songs.

It has been a tough year of change and healing for Sophie (Amanda Seyfried), who is preparing for the grand re-opening of Hotel Bella Donna without the aid of mother Donna (Meryl Streep). As she, new manager Fernando (Andy Garcia), and dad Sam (Pierce Brosnan) make last-minute preparations while awaiting the arrival of their guests, the hands of time turn back to 1979, when new college graduate Donna (Lily James) experienced a life-changing summer that led her to her future home on the Greek island of Kalokairi. The three potential suitors she met on her travels—beguiling, virginal Brit Harry (Hugh Skinner); coolly flirtatious Swedish sailor Bill Anderson (Josh Dylan); and sensitive Irish-American architect Sam (Jeremy Irvine)—would eventually lead to Donna's pregnancy with Sophie. Any one of them could be her father and, as she came to discover in the first picture, she didn't really care which one because she loved them all.

"Mamma Mia! Here We Go Again" is wispy and wistful, a film with a number of big laughs but also a somewhat sobering undercurrent. The entire central cast of "Mamma Mia!" returns along with several welcome new faces, and the reunion atmosphere on top of ABBA's irresistible catalogue go a long way in smoothing over the virtually barren forward momentum of the plot. In the present-day scenes, Amanda Seyfried (2015's "Love the Coopers") leads the charge as Sophie, determined for the hotel re-opening to go off without a hitch while missing husband Sky (Dominic Cooper), currently grappling with a job offer in New York. She and Dominic Cooper (2014's "Need for Speed") are given a forgettable duet to "One of Us" early on, but an easy highlight is the delightful "Angeleyes" which Seyfried performs alongside Christine Baranski (2014's "Into the Woods") and a hilarious Julie Walters (2018's "Paddington 2"), as Donna's best friends Tanya and Rosie. Notoriously shaky warbler Pierce Brosnan (2014's "A Long Way Down") is thankfully given few chances to sing as Sam; it's dramatically for the best that he only has to hum "SOS" this time around in a quietly affecting moment. As Sophie's other two dads Harry and Bill, Colin Firth (2017's "Kingsman: The Golden Circle") and Stellan Skarsgård (2015's "Avengers: Age of Ultron") are good sports in smaller roles, giving their all during the large-scale, exquisitely mounted "Dancing Queen" number, which effectively bridges the second and third acts.

In extended flashbacks, Lily James (2017's "Baby Driver") is radiant and a terrific singer, to boot, as young Donna. She doesn't really look much like elder counterpart Meryl Streep (2016's "Florence Foster Jenkins")—who pops up, it should be mentioned, in a bittersweet cameo—but she does capture Donna's restless spirit and grounded humanity. James' opening number, the graduation-set "When I Kissed the Teacher," is a delight, as is "Waterloo," a sprightly duet she shares in a French restaurant with Hugh Skinner's (2016's "Kill Your Friends") young Harry. And then there's Cher (2010's "Burlesque"), receiving an entrance fit for a queen as Sophie's glamorous, semi-estranged grandmother Ruby Sheridan (Cher)—a woman Sophie amusingly describes as having not been seen outside of Las Vegas in decades. The character doesn't quite fit her description from the original "Mamma Mia!" (never mind it was even hinted that she was deceased) but it scarcely matters when a legend of Cher's stature shows up and absolutely slays the sultry love song "Fernando."

"Mamma Mia! Here We Go Again" seemingly evaporates as it plays out but is a frequent joy to behold while it's happening. The connectivity between the previous film and this one isn't seamless—Donna's rendezvous with Sam, Bill and Harry, previously established in diary entries, do not quite match the flashbacks herein—but if fans are able to forgive for this messiness and go with the flow, they'll be enjoying themselves too much to care. In a melodic concoction of bubbles and froth, writer-director Ol Parker does take time to consider the people we cherish who are no longer with us, and a late scene performed to "My Love, My Life" gives its closing moments a certain graceful gravitas when it needs it most. "Mamma Mia! Here We Go Again" is light and starry and the name of the game, above all, is the wonderful ABBA music, pulling everything together as if the tunes were written precisely for this moment in the cinematic spotlight.