A new, six-part limited-series adaptation of Walter Mosley’s 2010 novel, The Last Days of Ptolemy Grey, is an offbeat pseudo-mystery with an intriguing science-fictional setup. Its most notable element, though, is the work of its star, Samuel L. Jackson, who gives one of the finest performances of his career. Its first two episodes premiere on Apple TV+ on March 11.

In the Kirkus-starred novel, Ptolemy Grey, an elderly Black man in 2006 Los Angeles, struggles with severe dementia, which makes it difficult for him to remember things and properly take care of himself. One day, his loving great-grandnephew, Reggie, who regularly visits and helps with everyday chores, is killed in a drive-by shooting, and the identity of his killer remains a mystery. A sympathetic teenage girl named Robyn, whom Ptolemy meets at Reggie’s wake, decides to help the old man; she cleans up his disastrously messy apartment and fixes its plumbing, allowing him to live much more comfortably, and becomes his constant companion. It turns out that one of the last things that Reggie did was consult a social worker about possible treatment for Ptolemy, and the social worker puts Ptolemy and Robyn in touch with the shady Dr. Bryant Ruben. He offers a dangerous experimental drug therapy that could allow the old man to regain his memory and think much more clearly—but only for a short amount of time. Ptolemy elects to take the drug, which gives him access to many long-lost recollections, including conversations with his childhood mentor in Mississippi, Coydog McCann, who possessed a treasure that he passed on to Ptolemy; moments with his late wife, Sensia, with whom he had a volatile relationship; and traumatic experiences, such as the death of a childhood friend. Ptolemy also uses his newfound clarity to look into who killed Reggie—and to make sure justice is done.

Mosley takes his time getting to the temporary miracle cure, which finally appears around the novel’s halfway point. Its effect is impressive, as it allows Ptolemy to recall with clarity a number of events that are only hinted at in the book’s first half, which Mosley impressionistically sketches as flashes at the edges of Ptolemy’s consciousness. A few minor mysteries are cleared up, as well; for instance, the old man finally is able to locate Coydog’s treasure, which he hid long ago. However, Ptolemy’s investigation into Reggie’s violent death feels anticlimactic; he simply asks a few questions and figures out the identity of the killer almost instantly. Readers looking for the private-eye thrills of Mosley’s long-running Easy Rawlins series will be disappointed—although Ptolemy’s story does take place in LA, like those mysteries. Oddly, the new limited series moves the action to Atlanta.

Mosley, the creator and primary writer of the series, saw fit to make other minor changes, as well. For one thing, the show gets to the wonder drug much earlier, and it focuses more sharply on the killing of Reggie, which is never far from Ptolemy’s mind. As in the novel, the SF and mystery elements aren’t especially well-developed, but they aren’t the main draw here, either; the series is mainly a detailed character study, and Jackson is more than up to the task. His portrayal of Ptolemy’s dementia is nuanced and thoroughly convincing; other actors might have made him a pathetic figure, or wallowed in the tragedy of his situation, but Jackson highlights the impressive strength that drives Ptolemy, even at his lowest points. When the old man gets his faculties back, the actor impressively reveals him as a force to be reckoned with.

Judas and the Black Messiah’s Dominique Fishback, as Robyn, is also remarkable, giving her character a depth and dimension that’s somewhat lacking in the novel. Indeed, the book seems to go out of its way to sexualize the 17-year-old Robyn: Ptolemy often gazes at her legs, and he smiles approvingly when another character says, “That little girl gotta backside on her that’s a crime.” The series gives their lively interactions plenty of screen time and keeps the affectionate relationship between Robyn and Ptolemy a platonic one (though it does preserve a discussion from the novel in which Ptolemy and Robyn consider that might have gotten married—if she were 20 years older and he 50 years younger).

The great Walton Goggins, of Justifed fame, portrays Dr. Ruben; one only wishes that the series were interested enough in the character to give him more scenes. Perhaps it’s it’s for the best—this is a tight six-episode production that never drags for a moment. Whatever the story lacks in suspense, it makes up with riveting performances. Fans of the book will appreciate the faithful adaptation, but the story feels almost secondary; it’s Jackson and Fishback’s brilliant work that linger in one’s mind.

David Rapp is the senior Indie editor.