Enhanced descriptions from Syndetics:

S. L. Huang's Null Set is the breakout sf thriller for fans of John Scalzi and Greg Rucka

Math-genius mercenary Cas Russell has decided to Fight Crime(tm). After all, with her extraordinary mathematical ability, she can neuter bombs or out-shoot an army. And the recent outbreak of violence in the world's cities is Cas's fault--she's the one who crushed the organization of telepaths keeping the world's worst offenders under control.

But Cas's own power also has a history, one she can't remember--or control. One that's creeping into her mind and fracturing her sanity...just when she's gotten herself on the hit list of every crime lord on the West Coast. And her best, only, sociopathic friend. Cas won't be able to save the world. She might not even be able to save herself.

Reviews provided by Syndetics

Library Journal Review

In Zero Sum Game, Cas Russell was able to take out Pithica, the organization of telepaths trying to create a better world through their control, but now the crime rate is spiking and Cas feels responsible. So, why not take on the crime organizations that are ramping up in Los Angeles? Especially since Cas's own mathematical abilities make her nearly superpowered. Except that Cas knows that her last battle with Pithica cracked open a secret in her memory, one she will have to fight for and against as it begins to affect her mind. Now she's on everyone's hit list and unsure of her own stability, whom will she trust when her world is crumbling? Zooming from external to internal conflict, Cas struggles with the choices she's made for the rest of the world, knowing that she may have no choice but to do that again. VERDICT Huang's sophomore novel brings us the same tight action, compelling characters, and mathematics magic as Zero Sum Game. Fans of the TV series Jessica Jones will enjoy meeting Cas.--Kristi Chadwick, Massachusetts Lib. Syst., Northampton

Publishers Weekly Review

This exciting SF thriller sequel to Zero Sum Game keeps up the pace and piles on the tricky twists. Cas Russell, an expert mathematician and crimefighter, is recovering from a mind-melding fight and adjusting to a life filled with false memories. While on the hunt for a notorious L.A. crime lord, Cas begins to lose her grip on reality, her mind invaded by a past and an identity she does not recognize. Increasingly paranoid, Cas soon believes her friends all have ulterior motives and goes digging. Her curiosity may prove to be her undoing, as her discoveries upend the tenuous stability of the L.A. crime scene. The gritty tone complements the backdrop and plot, and there is a geniality to Cas that endears her to the reader. As Huang weaves together a compelling bit of science fiction in the possibilities of overwriting memories and identities, Cas's existential struggles echo those of social media users wrestling with profiles and personas. Although the side characters have the tendency to fade into the background, the central narrative is still strong. Readers who appreciate suspenseful science fiction will enjoy this vigorous novel. (July) © Copyright PWxyz, LLC. All rights reserved.

Booklist Review

In this follow up to Zero Sum Game (2018), mathematical genius Cas Russell confronts personal demons as she deals with the aftermath of taking down Pithica s global network. Despite their sometimes murderous methods, Pithica's psychic control enabled them to keep relative peace in the world. In their absence, crime in Cas's home base of Los Angeles is spiking, and she's determined to find a math-based solution. Unfortunately, her encounter with a Pithica psychic has brought fragments of her mysterious and traumatic past to the forefront of her mind, interfering with her abilities in a way that may be fatal. She has an unexpected offer of help, but accepting his aid could mean that Cas loses herself. Huang brings back several familiar faces and a few new ones as she explores Cas's changing ideas about good, evil, friendship, and family. This volume answers a few questions and raises many more, leaving readers eager for the next installment. Action and superhero fans will enjoy this story of a powerful individual struggling with questions of identity and morality.--Anna Mickelsen Copyright 2019 Booklist