Looks like Apple TV’s upcoming adaptation of Isaac Asimov’s Foundation trilogy is well underway! Variety has reported that five new series regulars have joined the cast.

Like The Watch, the BBC’s upcoming Discworld adaptation, Foundation seems to be opting for gender-neutral casting. According to Variety, Lou Llobell will play Gaal Dornick, a “mathematical genius from a rural, repressed planet,” Leah Harvey will play Salvor Hardin, “the protective and intuitive warden of a remote outer planet,” Laura Birn will play Eto Demerzel, “the enigmatic aide to the Emperor of the Galaxy,” Terrence Mann will play Brother Dusk, “the eldest living member of the ruling family,” and Cassian Bilton will play Brother Dawn, “the youngest living member of the ruling family and next in line to be Brother Day.”

Previously, it was announced that Lee Pace will play Brother Day, aka the Emperor of the Galaxy, with Jared Harris playing Hari Seldon. David S. Goyer will act as showrunner, with Isaac Asimov’s daughter, Robyn Asimov, acting as executive producer alongside Goyer, Josh Friedman, David Ellison, Dana Goldberg, and Marcy Ross, according to Variety.

If you haven’t read it, here’s the book series’ synopsis, from the Barnes & Noble Collectible Edition:

A landmark of science fiction’s “Golden Age,” Isaac Asimov’s Foundation Trilogy–which comprises the novels Foundation, Foundation and Empire, and Second Foundation–has long been regarded a visionary masterpiece whose astonishing historical scope perfectly conveys science fiction’s sense of wonder. First published as a cycle of stories in the 1940s and ’50s, Asimov’s iconic trilogy has endured to become, like the author himself, a legend of science fiction. Set in the far future, Foundation envisions a Galactic Empire that has thrived for 12,000 years, but whose decline into an age of barbarism lasting some thirty millennia is imminent–if the predictions of renegade psycho-historian Hari Seldon are accurate. Hoping to shorten the interval of this impending new Dark Age, Seldon convinces the Empire’s Commission of Public Safety to allow him enact a diversionary plan–one full of surprising subterfuges and intrigues intended to create and protect a Foundation on which the future Empire will be erected. Foundation and Empire advances the story farther into the future, in which a technologically advanced Foundation triumphs over attacking forces of the collapsing Empire. Yet even as the Foundation emerges valiantly, in fulfillment of Hari Seldon’s scheme, at the far corners of the Empire a powerful mutant, whose existence was never accounted for in Seldon’s projections, emerges to overwhelm the Foundation and establish his own tyrannical version of the Empire. In Second Foundation, a new Second Foundation, whose whereabouts have been kept secret from the original Foundation for safety’s sake, asserts itself as the true fulfillment of Hari Seldon’s plans for the Empire–and thereby pits itself against a Foundation resentful of its usurped authority.

There’s no word yet on a release date or any plot details.