“The Nickel Boys” — a tense, nervy performance — is even more rigorously controlled than its predecessor. The narration is disciplined and the sentences plain and sturdy, oars cutting into water. Every chapter hits its marks. Even if your prose taste runs to curlicue and adornment (mine does), the restraint feels significant. Whitehead comports himself with gravity and care, the steward of painful, suppressed histories; his choices on the page can feel as much ethical as aesthetic.

The ordinary language, the clear pane of his prose, lets the stories speak for themselves (recalling Cora, the heroine of “The Underground Railroad,” with her skepticism of “words to pretty things up”). As in that book, while Whitehead is frank about the barbarity his characters endure, there are few scenes of explicit violence — most of it happens offstage. And none of the violence is exaggerated. A reverence for the victims can be detected in this refusal to sensationalize their suffering. Details are taken from life: The floggings with a leather strap lined with sheet metal and the oversize industrial fan used to muffle the boys’ cries come from the narratives of the White House Boys themselves.

Whitehead stages a philosophical debate of sorts between the two friends: Turner, who believes in the essential evil in people, and Elwood, who insists on their decency. A straight-A student raised on his grandmother’s conviction that “duty might protect him, as it had protected her,” Elwood is enamored with the message of Martin Luther King Jr. and the beauty and bravery of the civil rights protesters — “how the young men’s ties remained straight black arrows in the whirl of violence.” Even in Nickel Academy, he vows to make the best of it. “He consoled himself with the notion that he just had to keep doing what he’d always done: act right.”

He is disabused of this notion, brutally and repeatedly. But it would be a mistake to think that Whitehead is punishing the character for his naïveté. When young Elwood takes to writing idealistic letters to the editor, he adopts a pseudonym, Archer Montgomery, borrowed, as it happens, from the writer himself (Whitehead was born Arch Colson Chipp Whitehead). Debates around respectability politics, narratives of hope and uplift are ones Whitehead has explored consistently over his career (usually taking a Turner-like stance). “Hope is a gateway drug, don’t do it,” he writes in “Zone One.” An enslaved woman on the run in “The Underground Railroad” learning to read trips over a word: “Cora didn’t know what optimistic meant.”

Still, Cora ran. Elwood suffers enormously but preserves something of himself that Turner squanders. It is this paradox Whitehead keeps exploring: the foolishness of optimism but also the offense of despair, the complacency it ensures.

Whitehead has written novels of horror and apocalypse; nothing touches the grimness of the real stories he conveys here, of a cinder-block building that still stands, a school that was closed only eight years ago. Its starkness and irresolution recalls the historian Yosef Hayim Yerushalmi’s point that the opposite of forgetting is not merely remembrance. It is justice.