Critical Point, by S.L. Huang

Next in Huang’s series about Cas Russell, amoral heroine who uses math to kick ass. Although the action is frenetic, with Cas lurching from kidnapping to bombing to fighting off bioengineered guard dogs, the overall pace of the plot is actually almost too leisurely; hints about the shadowy organizations which may or may not be controlling her life remain just hints, and her moral and emotional development is also frustratingly slow. The other characters are refreshing, accepting her strangenesses and allowing her to develop at her own (very slow!) pace, without allowing her to get away with bad behavior.

Null Set, by S.L. Huang

Sequel to Zero Sum Game, which saw mathematical (anti) heroine Cas Russell claim victory, but possibly at the cost of her own sanity. She spends most of this book dealing with the fallout from that and (over)reacting in ways that make both friends and enemies nervous. Her motives are pure but her tactics are extremely questionable, and she gradually works herself into a corner from which not even she can plot a possible escape vector. Loved how the title was used in the plot; definitely wondering what will come next.

Zero Sum Game, by S.L. Huang

Cas Russell will do any job for pay, because it’s better than being alone in her own head. Her superpower is not casual violence (though there’s plenty of that) but sheer mathematical ability; she calculates vectors of people and bullets, and plots her way through fights, until she’s the only one left standing. (Huang has a math background, so the math is actually readable and not just gibberish.) A standard rescue starts to go wrong when Cas is suddenly being pursued by an enemy too big to handle; on top of that, her thoughts and emotions no longer seem like they are her own. Cas is a prickly, untrusting person who is nevertheless fiercely loyal to a certain few, and it’s a joy to watch her gradually opening up her circle. Between dodging bullets, of course. I thought that there was a bit too much new plot being introduced near the end, but then I found out it was the first of a series. What a delight! Bring on more Cas, I am looking forward to seeing where she’s going.