Compared with cinema’s menagerie of big-city talking animals, the ovine stars of the movie The Sheep Detectives lead idyllic lives: They sleep among cozy bales of hay. They graze on the English countryside’s beautiful, grassy hills. Each has been thoughtfully named by their beloved shepherd, George (played by Hugh Jackman)—there’s Lily, Mopple, Sebastian, Cloud, Ronnie, Reggie, Wool Eyes, Sir Ritchfield, and Zora. And every night, George reads murder-mystery novels to them; the flock has come to appreciate what makes a good whodunit.At first glance, the movie they’re in seems like the kind of unassuming barnyard romp made mostly to amuse kids—until George is murdered one horrible evening, leaving his fluffy family unmoored. The sheep decide to investigate his death, but their choice to become gumshoes turns out to be the least unexpected development in the film. Based on the novel Three Bags Full, by Leonie Swann, The Sheep Detectives is an audacious fable about how joy and sorrow go hoof in hoof. Much of the mystery that unspools will seem familiar to anyone who’s ever cracked open an Agatha Christie novel, and the sheep’s antics will bring to mind the many verbal animals across cinematic history: Paddington, Babe the pig, Charlotte with her web. But such nostalgic warmth only enhances the film’s sweetness. The result may just be the most tonally surprising feature of the year so far, a rare, unabashedly earnest PG-rated film that has enchanted audiences with the deceptively simple power of well-deployed tropes.[Read: A very silly movie about some very good dogs]The script, by the Chernobyl and The Last of Us writer Craig Mazin, deploys common notions about whodunits and talking-animal tales to its advantage. Several of the human suspects may appear to be obvious threats, but they are often in need of shepherds of their own. Even the butcher, who heads to George’s farm after the shepherd’s demise to scout how many creatures he may be able to slaughter, falls asleep as he literally counts sheep—a cheeky, economical gag implying he isn’t that devoted to bloodlust. The antics of the flock, meanwhile, get treated with much more seriousness. Consider the moment when Lily (voiced by Julia Louis-Dreyfus), the smartest in the group, discovers George’s body: She believes he’s not moving because he’s playing a game in which the first to twitch loses, and only accepts reality when Mopple (Chris O’Dowd) gently points out that George is dead. The scene, between two CGI creatures, feels profoundly real because the tone is so carefully balanced: Their guilelessness makes their exchange devastating, but not maudlin.With apologies to my own species, the sheep of The Sheep Detectives outshine the human characters at every turn. Lily and her cohorts are refreshingly intelligent, with their own traditions that they struggle to uphold or reject. There is, to put it in mildly dramatic terms, substantial lore the flock follows: It shuns a (wildly adorable) “winter lamb” simply because he was not born in the spring, and whenever anything upsetting occurs, the sheep collectively choose to wipe their memories; after George’s death, the despondent group almost opts to forget him entirely. As such, investigating the case tests their instinct to ignore what causes them pain and instead accept that fear, grief, and loss are necessary for a fulfilling life.That lesson, of course, isn’t new. But The Sheep Detectives pulls it off while juggling the beats of an engrossing crime thriller and the goofy humor of a Saturday-morning cartoon. That genre-mixing reminded me of Project Hail Mary, the science-fiction movie from earlier this year that contends with large-scale environmental disaster while starring a lovable faceless alien named Rocky. The two films share some obvious DNA: They’re both adaptations of novels, released in the U.S. by the same studio (Amazon MGM), involve sophisticated special and visual effects, and feature nonhuman characters that make me want to cry when I think about them. But more than anything, they commit to sincerity—a quality that’s become rare in today’s cinematic landscape of downbeat sequels, melancholy “comedies,” and grim plotting. In The Sheep Detectives, such devotion to emotional satisfaction makes even the most overused clichés seem fresh and affecting. For us human audiences, those feelings are hard to forget.