It’s strange to call an essentially tragic limited series magical, but the word applies to “National Treasure: Kiri.”


The four-part series fits squarely into the top tier of U.K. crime dramas, which means few characters start out with any contentment, and things deteriorate from there. But Jack Thorne’s writing for both seasons of “National Treasure” never slides into the lazy habits of misery porn. “Kiri,” like its predecessor, is both brisk and illuminating, providing compassionate and honest character studies.


Each character in the latest incarnation of “National Treasure,” as was the case with the stellar first version, feels alive and specific and believably capable of a great many things. Wondering what each person might do next gives the drama a thrumming undercurrent of suspense, but Euros Lyn’s direction allows “Kiri” to breathe at the right moments, too. It’s well-paced and contemplative, a tough combination to pull off, but “Kiri” makes it look easy.


It helps that each edition of “National Treasure” has featured a stellar cast. There’s no plot overlap between the first season and the second, but the production values and acting are of a similar high caliber. “Kiri,” which follows the fallout of a momentous decision of an English social worker, may recall “Happy Valley” for those who saw Sarah Lancashire in that Netflix crime series.


In “Kiri,” the great Lancashire plays Miriam Grayson, a veteran social worker who has a young girl named Kiri Akindele in her care. Kiri (Felicia Mukasa) has a Nigerian grandfather, Oluwatobi “Tobi” Akindele, who dotes on her. But the girl’s father, Nathaniel, is a former jail inmate with a violent past, and her mother, a former drug addict, is dead.


For years, Kiri has lived with an upscale, white foster family who loves her deeply. But Alice (Lia Williams) and Jim Warner (Steven Mackintosh) have a host of problems in their lives, not least a teenage son, Simon (Finn Bennett), who is more than a little strange. The couple’s final adoption paperwork is about to go through when Miriam decides to let Kiri have an unsupervised visit with her grandfather and his wife. A crime follows, and much of the story of “Kiri” is told through the lens of race and class.


The Warners, who are given a press liaison by the police, go on a media tour that makes them momentarily famous. The sympathy for them is as bountiful as is the hatred for the prickly (and relatively poor) Miriam, who thought it important to allow Kiri to spend time with family members who look like her. As a black girl, she would “othered” all her life, Miriam explains angrily to the reporters who wait on her doorstep after the case becomes national news. Miriam, who is white but has a multi-racial client pool, asks her bosses and media critics why Kiri shouldn’t be allowed to have a space in which that othering would not occur. Shouldn’t her biological family’s culture and values inform the girl’s life?


Some call Miriam’s decision — which conformed to social work protocols in her department — “anti-white.” And though she is partly to blame — and Lancashire depicts her regret with indelible, heart-rending precision — the system turns Miriam into a culprit, in large part so her superiors can avoid a series of thorny questions they would rather not contemplate.


But “Kiri” does not only examine its central crime from the perspective of white characters. The series’ revelation is an intense, complicated performance from Lucian Msamati as Tobi. His relationship with his son, his past mistakes, and his own soul-altering grief are all explored in mesmerizing ways. Though he is a very proper, religious man and no one’s idea of a radical, he slowly begins to accept the idea that the police are railroading his son — about whom he has his own doubts.


Both seasons of “National Treasure” explore the idea that family relationships can be the most treacherous terrain of all. Most characters in “Kiri” start to believe that they don’t really know the people closest to them, and the questions they have scare them. Miriam begins to seem exceptional because, despite having spent three decades seeing the worst of human behavior as a social worker, she still possesses a few scraps of optimism. She is innately kind, quick with a quip, and still visits those who were in her care decades ago, simply because she’s curious about how they’re doing.


As was the case with the first installment of “National Treasure,” a few story paths would have benefited from more exploration. In particular, the Warner family’s troubles probably needed a little more set-up, but that said, Williams, Bennett and Mackintosh are all exceptional in their roles. Also deserving of mention is Wunmi Mosaku as the lead detective on the Kiri case; like Miriam, she’s in a no-win situation. She is navigating a system that favors families like the Warners, and is also under pressure to find the tidy, predictable solution that the media clearly wants.


But the narrative of the case — and of “Kiri” — is as unexpected and contradictory as life itself, and that is its chief selling point.
Executive producers, Jack Thorne, George Ormond, George Faber.


TV Review: 'National Treasure: Kiri' on Hulu
Limited series; Four episodes (four reviewed); Hulu, Weds. April 4.
Cast: Sarah Lancashire, Lucian Msamati, Steven Mackintosh, Lia Williams, Finn Bennett, Wunmi Mosaku, Felicia Mukasa, Paapa Essiedu, Andi Osho, Sue Johnston