Null Set by S.L. Huang is the second book about Cas Russell, an amnesiac mercenary with a mathematical superpower. I enjoyed it, but felt the book was trying a bit too hard to hit similar notes to the first one; the stakes are upped because Cas’ own memories are, potentially, the Big Bad. The best part was the story’s exploration of gray areas of morality, particularly decisions made for people and their safety instead of by them, and where both types of choices can go wrong, and what a slippery slope that can be. I am assuming there will be more in this series? I’m interested to see where it goes.

I loved S. L. Huang’s Zero Sum Game, and Cas Russell, whose superpower is her ability to make lightning-fast mathematical calculations. She works at such irregular and occasionally dubiously legal jobs as tracking down missing persons, and enjoys an uneasy but devoted friendship with psychopath, Rio. At the end of the first book, a world-wide mind-control conspiracy had been defeated after many struggles and reversals. Null Set picks up where Zero Sum Game left off, with Cas and her gang facing rising gang violence, the result of eliminating the aforementioned mind control, and she herself beset by newly resurfacing memories of a previous personality, and a telepath bent on trying to help her before whatever was done to her to give her those memories kills her. Confused? So was I, for much of the story.

Alas, Null Set feels like either a sequel that author hadn’t planned on or the flabby middle book of a series. Cas spends way too much time agonizing over this or that, tormented by fragmentary memories, unwilling to ask her devoted friends for help, and in general not accomplishing much. When she hits upon a solution to the looming gang war, she only ends up having to undo it because if people are now unable to feed off each other’s anger, they are equally immune to sharing hope. Suicide and addiction rates skyrocket. I found myself wondering what the point of it was, since we would end up right back where we started.

It felt as if the ideas and plot of a novella or maybe an even shorter novelette got stretched out into novel length. I’d loved feisty, independent Cas in the first book, but now found her indecision, unwillingness to trust anyone, and general crankiness annoying. Even her very cool mathematical genius couldn’t compensate for the loss of sympathy as a character. There’s supposed to be a third book, but I think I’ll skip it and consider Zero Sum Game as a nice, tidy stand-alone.

Cas Russell is a math genius and a mercenary, on a crime fighting blitz in S. L. Huang's "Null Set". In the first entry in this series, "Zero Sum Game", she and her associates defeated Pithica, an organization of telepaths intent on making the world a better place - through murder and brainwashing. Now, criminal activities have increased and Cas feels she must do something about it.

In an effort to stop the escalation of crime that started after Pithica's defeat, Cas acquires and implements a frequency generation technology developed 'to break up mob violence'. Of course, this has all kinds of unintended consequences that Cas and crew then have to deal with.

Do read the first book before this one. I had not done so and found it difficult to catch up with the back story.

Null Set blows any genre expectations out of the water, combining science fiction, spy fiction, technothriller, and mystery to create an action-packed adventure that thrills on every page. With such a high stakes protagonist running from a convoluted past, it’s no surprise the book leaves your heart racing.

From page one, Huang never stops throwing in surprise revelations mixed with adrenaline-fueled action and high-tech lingo. It’s a thrilling ride thanks to the unexpected pathways diverging from the main narrative. One moment, you’re on a high stakes mission surrounded by gunman and impossible odds. The next, you’re privy to a deep conversation on hacking, followed by a theoretical discussion about experimental technology that sounds bonkers. Huang shows impressive inventiveness throughout.

The main character, Cas, is a fascinating character study. She flies between extremes on the regular, adding a number of surprise twists that will keep you guessing. She cycles between a strong desire to be alone and a fierce loyalty to her strange chosen family. Her struggles with the relationship between free will and crime fuel the primary thread of the book alongside the mysteries of her past. Add in her superhuman mathematical abilities and you've got a brilliant character you want to understand. There’s never a dull moment in the world of Cas Russell.

Overall, Null Set is a wonderful addition to multiple genres, highlighted by a badass protagonist and a complicated plot that keeps you guessing. Get ready for a high stakes adventure.

Review to be published on 8/6: http://reviewsandrobots.com/2019/08/06/null-set-book-review

Ahoy there mateys. I tried to read this one multiple times and couldn't get into it. So I was going to give up on this book. Then I learned it was a book two! Well no wonder I was confused. So I am going to set this aside for now and come back to it once I have read the first book. Arrr!

I'm unaware of any other authors who are doing what S. L. Huang has done with her Cas Russell series, but I'd love to read them if they're out there, because she leaves you wanting more. Null Set is definitely a middle book, bridging between Zero Sum Game and the next book, with a cliffhanger ending that for once I do not mind. I also don't mind that I can't think of other books to compare this to—only movies. If you like superhero movies, Chinese martial arts movies, and movies like The Matrix and The Fifth Element, you'll definitely be into this dark, gritty futuristic thriller and its gifted and violent anti-heroine. If you can imagine superheroes on steroids, if you dig movies like John Wick and Fast and Furious, that's when you enter S. L. Huang territory.
Read Zero Sum Game first; it takes a while to remember how the first book made you sympathize with Cas; she's an antihero because she's not very likeable, but you root for her anyway, like her friends do. You get little character studies in the action between the action, but you are dropped full tilt into the current situation. Cas can calculate angles so quickly that she can shoot, sprint, jump and punch her way out of most dangerous situations. She and her pals are on the track of and on the run from the evil future corporation that messes around with people's heads, commits the occasional assassination trying to make the world a better place—their way. Hunters and hunted at the same time, perfect action movie plot.
It's really a gift to be able to put a movie on the page like this, to have just enough depth amidst heart-pounding suspense, enough detail but not drown the reader, enough rush for picky readers to not notice any discrepancies. Huang has taken her film and stunt experience and made it work in novel form. Most attempts at writing for adrenaline junkies fail; these books succeed. I am half "give me the next book now" and half "cliffhanger? Never said this before, but ok, maybe in 6 months to a year my heart can take it."
Highly recommended for action fans and adrenaline junkies.
(I received an advanced electronic copy for review, thanks to Netgalley and Tor.)

★ ★ ★ 1/2 (rounded up)
This originally appeared at The Irresponsible Reader.
---
In the aftermath of Zero Sum Game, Cas and her associates are seeing the fallout from taking down those telepaths who've been reigning in expressions of human corruption, and it's not pretty. So, she takes it upon herself (with a little help from her friends) to fight crime in LA -- à la that rich guy in Gotham, that lawyer in Hell's Kitchen, or the sole survivor of the Cavendish ambush of the Texas Rangers. She's making a difference, but not as much as she wants, until she decides to take a more proactive approach.

I'll skip the details, but what she comes up with (and talks her team into helping with) is a combination of technology, psychology and her genius. It's so successful that every major criminal figure in LA would happily kill her several times over if they only knew what she was doing and who was doing it. Of course, many of these people are former/potential future customers. This little dance she does, while trying to get the goods on one player in particular, is a whole lot of fun to watch.

It's also fascinating watching Cas' develop a conscience, and then let it take her in ways that bring her into conflict with her team. They go along with her, but with reservations. In many ways, she's grown from the woman we met in the opening of Zero Sum Game -- but in so many ways she hasn't. The heavy drinking she indulges in/retreats to testifies to that.

One thing that happened at the end of the previous novel was that a telepath triggered something in her -- how much of an effect this had, or whether it was time, or something else (probably a combination of the three) has loosened something in her subconscious. Memories -- partial, confusing, scattered -- are coming back to her -- from a time that Cas had given up on ever remembering. The memories come back, unbidden, at the worst possible times and make her vulnerable when she needs to be focusing. They also point to mysteries, questions and so many unknown things that Cas decides she's not going to acknowledge that this is problematic for her, her work and those who depend on her.

My problem is that I think Huang overestimated how interested people were in Cas' background and trying to learn about it/deal with it. Maybe it just feels that way to me because I can't muster up the level of enthusiasm that the novel seems to want me to have, and everyone else will be hanging on every word. What Cas is going through has roots in the conclusion to Zero Sum Game and in her murky past. Instead of dealing with the memories and issues they raise, she spends most of the novel running from the problems, not in denial, just in a refusal to work through them -- until she can't any more (and even then . . . ). If I knew her better, if I was given more of a reason to be curious about her past, I think this could be a very interesting plot line But we don't, and we're not -- and I had a hard time getting above the level of mild interest in this part of the novel. Which isn't good -- because this is what the novel really wants to talk about, not Cas' innovative solutions to fighting crime.

For people who haven't read Taylor Stevens' Michael Munroe novels, this paragraph won't do much for you. You should read those, by the way, if you like Cas Russell. In the second book in this series, The Innocents, Stevens takes Munroe -- her complicated, almost impossible to believe, hyperviolent protagonist with a self-destructive bent (hmmm, who does that sound like?) -- and has her deal with some of her problems, taking a deep dive into her psyche at the risk of the job she's taken on -- and the innocents she's supposed to be rescuing/saving. I'd liked Munroe in her first book, and continued to, but I struggled getting through that book -- but once Munroe had dealt with (in some way) what was getting to her, she was a stronger and more interesting character. I cannot tell you how often while reading Null Set that I thought back to The Innocents. True, very different books, different problems plaguing the protagonists -- but their reactions to the issues and how they intend to deal with the problems raised, remind me greatly of each other. I'm hoping what comes next for this series is as strong as it was for Stevens'.

Everything else about this novel was just as absorbing and captivating as Zero Sum Game. The supporting characters were, if anything, more interesting than they were last time -- and the two new characters in Cas' circle were welcome additions. The ethical dilemma posed by Cas' actions was pretty interesting, and a good twist on the similar conundrum posed in (and, arguably, less clear -- although, I'm with Checker in not seeing it that way). The characters' reactions to her plans (and carrying them out) seemed authentic and not just something to create drama. If Huang had wanted to and just dialed back the A-Story and dialed up the B-Story, I'd have been more enthusiastic about this -- probably as much as I was about Zero Sum Game, maybe moreso.

And you just cannot beat Huang's combination of math and fight scenes -- others dabble in it, but most don't go as far (they're probably not that good at math) or do it as well. I don't know why these scenes work so well for me, but I just love them. Think of River Tam wielding a gun in "War Stories" -- but if she was able to tell you what she was doing and why without sounding a little . . . well, River-like. I'm not doing a great job of describing it, but it's hard. But if Huang decided she just wanted to publish a novella or two that really just consisted of fight scenes without a whole lot of plot? I'd be all over them. Nothing against plot or characters, but sometimes they just get in the way.

I did like Null Set -- just not as much as I expected to, or wanted to. But I'm still in for more of this series. What Huang's set up for the next novel (or more) -- really has my interest. The possibilities for book three have really got my curiosity churning. Having (somewhat/largely) dealt with these issues around Cas, the door is wide open for what comes next -- I literally can't wait. This isn't what I wanted from the second Cas Russell novel, but it's good -- and will likely be a strong foundation to build on. Recommended.

Disclaimer: I received this eARC from Macmillan-Tor/Forge via NetGalley in exchange for this post -- thanks to both for this.

Null Set by S.L. Huang as it turns out is actually the second book in the Cas Russell series. If only I realized that before I was approved for it. I totally should have read book one, Zero Sum Game, first but either way this still ended up being a pretty great read on its own. I liked getting to Cas herself because her abilities are cool - her genius mathematical skills give her superhuman accuracy and timing - verging on magical. She's flawed but an intriguing figure. The characters themselves were my favorite aspect of the book. Overall, I want to know more about Cas and her world, so I believe I may have to go back to check out the first book in the series.

My first experience with SL Huang was listening to her speak last year at New York Comic Con and thinking that she sounded cool and funny. That’s why I bought Zero Sum Game when i saw it pop up on a kindle daily sale. It was great! A little more murder-y than my usual taste in SFF but a really good story that kept me guessing.

Null Set, the second Cas Russell novel, was even better. I was lucky enough to get an eARC from the publisher on Netgalley and I couldn’t put it down! A real leveling-up by the author. The characters’ voices seem much more well-defined in this volume and the protagonist’s psychological journey felt very real. I can’t wait to learn more about her backstory in future volumes.

The story is still more murder-y than I usually go for, but I really appreciated the fact that several of the characters are as uncomfortable with the level of violence as I am. I am still a bit bothered by the stereotypical genius tech nerd in a wheelchair character. While I like to see the representation, the character often comes off as a trope and a plot device then a fully realized person. Furthermore, it seems like the author often forgets that he is in a wheelchair - I can’t imagine that every locale he ends up at is totally ADA compliant, and it sometimes took me out of the story.

Overall, a very enjoyable second book in a very interesting series. Can’t wait for book 3!

I read Zero Sum Game last year and enjoyed Cas Russell's character and her new crew's fight against the telepaths. But at the heart of it, Cas is the draw of this series. The vectors and statistics, the automatic mathematical deductions, and her mysterious past... She's a loner who now has a 'found-family' in Arthur, Checker, and Pilar. Cas still finds it odd to trust people, but she does and she knows she is better for it.

The beginning of Null Set finds Arthur and Cas trying to break up a child smuggling ring that has ties to a mastermind gangster who oversees much of the illegal operations in the Los Angeles area. The gangs are mad that these Cas and her crew have chosen to mess with their  moneymaking, so they strike back...  and the plot takes a left turn when Cas's memory starts shorting out. Images and clips from her past start appearing in the midst of gun fights as if the adrenaline is triggering these brain seizures. And then a ghost named Simon intercepts Cas leaving Checker's place. He knows things and is somehow connected to Rio.

I'll leave the plot summary there and give you my thoughts about this sequel to Zero Sum Game... I thought it was an interesting choice for Huang to change the sequence of her original novels. This was the plot of the 4th book and it seems like as thriller/ detective series goes, that is a good place for it. The basic plot line of this genre usually includes an opening action scene, intro of new bad boss man, and then some plot twists and a bang-up ending. I did not expect so much introspection and character reveals in a second book. I thought there would be a couple more books to get to know Cas before getting too deep. 

Is this a bad review? I'm not sure. I still like this character, even though she reverted a little back to angry loner in this one a bit. And I think Huang writes tremendous action sequences and I buy in to every description of mathematics she writes. I just thought this was a ill-placed in the series.

3 out of 5 stars.

"I have superpowers, too," I said. "I use them."
"Yours are different. You don't...unmake people."
"No, they just underestimate me and then I kill them."

Hot damn, this book! To say I couldn't put it down is an understatement; two days, a couple pots of strong-ass coffee, and three lattes later Null Set was toast. Also, I might be an emotional wreck right now, of this I am unable to confirm, nor deny.

ZERO SUM GAME was so my thing, it backed its moving truck into my garage. Its sequel, NULL SET, made itself at home, snuggling up with me on the sofa and stealing the remote. Cas Russell, flawed, troubled, loyal AF, math genius Cas has returned, and this time, she has a found family to care about as she makes one terrible decision after another trying to save Los Angeles from the fallout of her crew's strangling of Pithica's influence. But her past is haunting her, quite literally, and might be her downfall if she can only figure out who she should trust.

I loved getting to know Checker and Arthur more, as well as the newest member of Cas's crew. And, of course, Rio. Perhaps we're meant to fear him, but not this reader. The conflict between Cas and Rio drained my soul, brought me to tears, and almost had me throwing my iPad across the room I love/hated it so much. That I have to wait for the next book to find out more has me aching for July 9th so that I may read NULL SET again. All the stars!

3.5 stars, Metaphorosis Reviews

Summary:
Cas Russell, whose mathematical ability allows her superhuman timing and accuracy, has faced down a network of telepaths. But now trouble has come to her own home time of Los Angeles, just when her past seems determined to destroy her.

Review:
S. L. Huang first self-published the Russell’s Attic series, only to have it taken up, edited, and re-issued (in a different order) as the Cas Russell series. I read the first book in this series, Zero Sum Game, in its original version, and this (now) second book in the reissued version. It’s therefore not to surprising that there are significant discontinuities between the two – and that’s with having read the first book only a few months back. It takes a few chapters to catch up with the new situation, but then it’s fairly smooth sailing. The book overall, however, is less of a success than than the first. While I’ve given each 3.5 stars, the first book leaned high, and the second leans low.

Cas is still her messy, likeable self, but in this book, she veers heavily toward Thomas Covenant territory – with a blindingly obvious path before her that she adamantly refuses to take. That intensely frustrating approach worked for Covenant because that was an essential part of his character. Here, it’s just frustrating – it feels like a clunky, heavy-handed authorial attempt to create tension, and Cas’ introspective defence of her actions just isn’t convincing. That’s compounded by an amnesia plot-line that crops up constantly, but simply isn’t interesting; it feels tired.

Cas’ mathematical abilities continue to be a little too all-powerful and magical, and some of the other plot points aren’t too credible either. What saves the book is the strong characterization. Cas is engaging, sympathetic, and interesting. But even there, the book begins to fall short. She suffers substantially from Good Guy Arrogance – doing what she likes for the greater good, ruining people’s lives left and right, and yet they all forgive her and fall over themselves to put her at the center of their lives. It’s not clear why. She’s got a superpower, and she’s interesting, but I think she’d be hell to spend very much time with.

The book skates through on the strength of its characters and second half, but frankly I’d have preferred to see the major plot line deleted, and this presented as the first half of a different book. Much of this one feels like it’s deliberately prolonging the mystery of Cas’ origins that we’re all really interested in. Maybe I should have gone back to the original version (#3 in that version of the series). Certainly, I think the self-published book 1 was stronger than this professionally published book 2. Worth reading, but not what I hoped for. Here’s hoping the (new) book 3 is more focused. I have to give Huang credit again for a really thoughtful attempt (via her website) to help readers bridge the gaps from one version of the series to another.

I received a free copy of this book in exchange for an honest review.

I hate to say this, but I LOVED Zero Sum Game, and I DID NOT enjoy Null Set. Three quarters of this book was Cas lashing out at her friends and and being stubborn and belligerent. By the mid point I was so annoyed by her I didn't really care what happened to her. Yes, she had stuff bad wrong with her, but everybody (including her) knew the only way to fix anything was something she didn't want to do, so she spent half the book fighting with them about it. And the sick, wild action that made the first book amazing was almost completely absent. I don't care about her calibrating energy waves, I want to read about her riding a motorcycle up the side of a building and jumping into a helicopter while shooting 57 bad guys dead without missing a single one.