When Eva Husson’s lush, aching period drama opens, World War I has been over for more than five years. Textbook history suggests that its end kickstarted all the fun and frisk of the Roaring Twenties, but “Mothering Sunday” handily dispels that myth. It’s 1924 and, as the world moves on, a trio of bereaved families in the UK’s Berkshire County do their damnedest to pretend that they are, too. Hyper-observant orphan maid Jane Fairchild (a luminous Odessa Young) is about to embark on the rare day off, the “Mothering Sunday” of the film’s title — March 30, 1924, to be precise. Adapted from Graham Swift’s delicate novel of the same name, Husson sets her film mostly within that one, luminous early spring day. Alice Birch’s script adheres to Swift’s kaleidoscopic shifting settings, moving between Mothering Sunday and two later periods in Jane’s remarkable life. Some viewers might feel a sense of whiplash as the filmmaker slides between time and place at whim, but the strength of the film’s emotion and talented cast (Young is joined by a murderer’s row of stars, including Josh O’Connor, Colin Firth, Olivia Colman, and Emma D’Arcy) help ground it. The grand lesson that “Mothering Sunday” teaches, and the one Jane must learn, tragedy after tragedy: None of this, the pleasure or the pain, is ever permanent.

That gamble does not always pay off and Husson (“Bang Gang: A Modern Love Story”) often strips her film of its immense pleasures by cutting short key scenes and lingering on others that feel less vital. As Jane remembers her own life — and lives through it again and again — why not let us savor both the good and bad, to linger on the story of a woman who overcame so much and took the craziest of bets: to love, and to keep loving. “Once upon a time,” the film opens in haunting voiceover, “before the boys were killed,” lived a happy trio of Berkshire “clans” woven together by affection and common concerns. Paul (O’Connor) is the remaining Sheringham son, and while that has not robbed him of his kind countenance, there is a brittleness that is hard to shake. Paul is engaged to the only other remaining child from the trio of families, Emma Hobday (D’Arcy), who was once almost engaged to James Niven, the now-deceased son of Mr. and Mrs. Nivens (Firth and Colman) who employ young Jane. Like Paul, they are kind, if removed, and Jane’s job in their quiet home seems to be fine enough. On Mothering Sunday, the families plan to gather — as they did in the old days — to celebrate Paul and Emma’s imminent wedding; the rest of their help enjoys a day off to do whatsoever they choose. What Jane chooses is not a surprise: She slips off for a final meeting with Paul, with whom she has been locked in a passionate relationship with since her earliest days at the Niven household. They know it will likely be their last dalliance and do they ever make the most of it. Husson lavishes them and us with dreamy, sticky sex scenes that will likely appeal to the “Bridgerton” crowd — and, in a later period, an older Jane reflects on the day as she tries to commit it to her next novel, having broken loose of domestic duties and become a writer.

Jane has plenty of material, and Husson even flashes further forward to find an elderly Jane (Glenda Jackson) enjoying her career. Mostly, though, the film flips between Jane’s last day with Paul and her life some years on, including a romance with the gentle Donald (Sope Dirisu), who only encourages her desire to commit her relationship with Paul to paper. The slipstream of memory unfolds across the film, with Young binding two very different performances, the bright-eyed young maid and her more world-weary elder counterpart (distracting and unnecessary makeup attempts to age her for the character’s post-housemaid, pre-Jackson portrayal). Everyone in “Mothering Sunday” has to make sacrifices, we’re told — a resolute Paul tells Jane, “I’ve got to get married, I’ve got to become a lawyer,” a mantra that seems to exist to remind him of his place in life — but Husson’s film makes it clear that Jane might be the only one able to break free of those expectations and do something different. The Nivens, broken and breaking, have already made their sacrifices and will likely never survive them. Emma has endured her own heartbreaks, and D’Arcy’s seething performance makes it plain that she will probably always be, rightly, pissed off about that. They are all crumbling, and it’s only Jane who can make sense of it. Later, Donald will term Jane’s time as a maid one that made her “an occupational observer of life,” and “Mothering Sunday” similarly seems preoccupied details big and small. Lingering close-ups of everyday items like buttons and blooming flowers are treated with the same reverence and care as a revelation about what becomes of Paul. All of it is suffused with pain and pleasure, memory flattening experiences to be so very black-and-white. “Mothering Sunday” pushes toward cut-and-dried conclusions, sewing up certain storylines with a finality that doesn’t befit the early sense that nothing is really ever over for Jane or the wounded world she inhabits.

Grade: B-

“Mothering Sunday” screened at the 2021 Toronto Film Festival. Sony Pictures Classics will release it later this year. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.