That's because writer-director Ol Parker keeps things lively even with mourning in the background. He's well-primed to do so: Parker is best known for writing the Best Exotic Marigold Hotel movies, both of which let mortality hang over their heartwarming antics. Here, he also gets an assist on the story from Richard Curtis, the rom-com genius behind Notting Hill and Love Actually, who is as adept at making people sob as he is at making them swoon.
So action cuts back and forth between the past and the present as Downton Abbey's Lily James assumes Donna's adventurous persona for extended flashbacks, turning the affair into a hybridized prequel. As Sophie preps the opening festivities -- and frets over her relationship with her fiancee Sky (Dominic Cooper), who has a big job offer off the island -- young Donna is meeting hot men and starting mischief. The moments in the past don't offer any further explanation as to who Sophie's dad is -- or why Donna wasn't using any protection in the late '70s, for that matter -- but they are nonetheless cheery, romantic, and not at all slut-shame-y.
A particular winner is the "Waterloo" sequence staged in a French restaurant where Harry (Hugh Skinner taking on Colin Firth's youthful counterpart) convinces Donna to spend the night with him. (And, in turn, take his virginity.) There's a chorus of dancing waiters in Napoleonic garb! Later, Donna frees a horse. This detail is neither here nor there, but I think it's worth mentioning.
Indeed, the initial Mamma Mia! did use up a bunch of ABBA's more recognizable tunes in its narrative, which means you'll find a lot of the group's deeper cuts here, like the truly bizarre "When I Kissed The Teacher." There are some reprises of classics, however, because what would this enterprise be without the title song and "Dancing Queen," after all?