Rosa, also known as Red Riding Hood, is done with wolves and woods. Hou Yi the Archer is tired and knows she is past her prime. Both would rather just be retired, but that’s not what the world has ready for them. When deadly sunbirds begin to ravage the countryside, threatening everything they’ve both grown to love, the two must join forces. Now blessed and burdened with the hindsight of middle age, they begin a quest that’s a reckoning of sacrifices made and mistakes mourned, of choices and family and the quest for immortality.

Math-genius mercenary Cas Russell has stopped a shadow organization from brainwashing the world, and discovered that her past was deliberately erased and her superhuman abilities deliberately created. And that's just the start. When a demolitions expert targets Cas and her friends, and the hidden conspiracy behind Cas' past starts to reappear, the past, present and future collide in a race to save one of her dearest friends.

Math-genius mercenary Cas Russell has decided to Fight Crime. 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’ fault --- she’s the one who crushed the organization of telepaths keeping the world’s worst offenders under control. But Cas’ 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.

Cas Russell is good at math. Scary good. The vector calculus blazing through her head lets her smash through armed men twice her size and dodge every bullet in a gunfight, and she'll take any job for the right price. As far as Cas knows, she’s the only person around with a superpower...until she discovers someone with a power even more dangerous than her own. Someone who can reach directly into people’s minds and twist their brains into Möbius strips. Someone intent on becoming the world’s puppet master. Cas should run, like she usually does, but for once she's involved. There’s only one problem: she doesn’t know which of her thoughts are her own anymore.