Planetfall was Newman's first science fiction novel and is about a 3D printer engineer in a colony on a remote planet inhabited by a large bio-mechanical alien structure called "God's City".

Twenty years before the beginning of the novel, Renata Ghali (Ren) befriends Lee Suh-Mi (Suh) when both women intend to rent the same apartment in Paris.

A small group including Suh, Ren, Mac, and Hak-Kun land first and explore a large bio-mechanical alien structure they call "God's City".

With Ren sworn to secrecy, Mac establishes a colony at the foot of God's City, and institutes an annual ritual in which the colonists gather to await Suh's return.

Still traumatized by her persistent love for Suh and the secret she's forced to keep, Ren has become a loner, compulsively hoarding objects she steals from the colony's recycling systems.

While the colonists escort Mac and Ren to be imprisoned pending trial, sudden explosions destroy the colony's vital infrastructure.

Other survivors attack, acting on Sung-Soo's pre-arranged plan to destroy the colony and return to the wilderness with a few people designated as vital.

By placing her faith in its creators and removing her protective equipment, Ren adapts to the environment inside the city and passes several trials as she works her way up through the megastructure.

At the top, where Suh died twenty years before, Ren enters the final room and discovers an alien body lying on a slab.

[8] He said Ren's first-person narrative gives the reader "a very limited perspective" of her world, which makes her voice "haunting" and suggestive of "dread lurking beneath the surface".

[8] He compared Planetfall to Mary Doria Russell’s novel The Sparrow which also deals with an uneasy truce between science and religion.

[8] But overall Bedford described Newman's book as "[b]eautifully and heartbreakingly wrought" and called it "a distressing, harrowing novel that left a deep mark on me".

Writing at Gizmodo she described the book as "much weirder", "a fair bit darker", and with as much psychological drama as science fiction.

Anders remarked that Newman's use of a first-person narrator who does not reveal all she knows is "risky", but felt that here, with all its "repressed truths and terrible secrets, it absolutely works and feels natural and honest".