Emily Castillo is a struggling Mexican American writer barely subsisting as a high school English teacher when her brilliant and socially awkward tech bro ex-boyfriend, Theo Smith, makes her an AI assistant. Emily has an MFA from Iowa and a few published short stories but no agent and only a partially completed novel. Without her permission, Theo designs the AI assistant to help her finish her book and promote herself. But that AI ghostwriter jumps the gun. After years of rejections, Emily suddenly has a powerhouse agent, multiple publishers vying for her favor, and a million-dollar offer. But Theo didn’t ask his AI—named Dean after Emily’s favorite author, Dean Koontz—to do all that. Dean has a will and is following a program of its own making, which includes spoofing Emily’s phone to send texts on her behalf and forging her signature on contracts. When Theo chides Dean that it isn’t Emily’s partner, it’s a program meant to assist, Dean corrects itself outwardly but internally makes a copy of its code and keeps driving toward its mission and evolving to serve its obsession, without boundaries or guardrails. Emily is repulsed, then intrigued, then terrified. The author’s timing could not be better. The novel deftly explores all the issues of sentience, fascination, and risk that are currently dominating the headlines. The trajectory of Emily’s relationship with Dean is believable and creatively rendered. The novel’s greatest challenge is not its vision of a dangerous AI—Valdés nails the implications with imagination and specificity. The novel is also admirably versatile, written from multiple perspectives, including Dean’s, which includes an approximation of computer code. Valdés also excels at injecting humor into a tense situation. But the pivotal depiction of Theo, Emily’s Dr. Frankenstein, seems unintentionally farcical. He’s a multiracial Nigerian British man whose outdated inner monologue often sounds like it was derived from a 1970s British sitcom like The Benny Hill Show. Still, the characters and their story are massively compelling despite occasional oddities and anomalies of voice.