Actress Celia Cross is famous, both as the daughter of Hollywood royalty and as a star in her own right on the daytime drama Doctors and Lovers. Then she’s involved in a car accident that makes headlines in the tabloids, leaving her with two broken legs and other scars that are slower to heal. She withdraws from the limelight to her Malibu home while she decides what she wants to do next. One night while walking on the beach, she finds a man washed ashore, barely alive with a bullet wound on his side. She’s about to call 911 when he tells her not to. Naturally she doesn’t, because heroines in romance novels always find reasons not to take such a sensible course of action. In this case, Celia isn’t any more interested in drawing attention to herself from the police and media than he is.

Undercover agent Roy Starr was on a mission to infiltrate the yacht of a Middle Eastern playboy suspected of trying to smuggle a weapon of mass destruction into the country. Caught in the act of placing a monitoring device on the ship’s computer, he was beaten badly, shot and dumped overboard. Celia nurses him back to health, and once he’s well again, she might be the key to his mission. Abdul Abbas al-Fayad moves in the same Hollywood circles as Celia, and she might be able to get Roy an invitation to the yacht. All she has to do is introduce the men by pretending that Roy is a Canadian millionaire and she is his new mistress. Celia is more than willing to help out, excited about the opportunity to do something useful instead of continuing to wile away her days. Roy is less convinced about this plan, not wanting to put her in danger, especially since he is developing feelings for her.

Kathleen Creighton’s story is exceptionally well-written, with the depth and detail in her prose that is increasingly lacking in the series romance world. The story gets off to a nicely atmospheric start, with Celia, unable to sleep, wandering the beach late at night. Roy’s experiences before Celia finds him are nicely shown with a number of flashbacks as Roy murmurs in his sleep, reliving what happened as Celia sits by his bedside, listening to his mutterings. For the most part, the story is character-driven without much action. Roy’s recuperation lasts for nearly the first hundred pages of the book, and the undercover mistress plotline takes a while to develop, but it never feels slow or boring thanks to the author’s smooth and engaging writing.

Eventually, Roy and Celia embark on their undercover mission. This part of the story is a little hard to believe, though Creighton does her best to make it as persuasive as possible. I only halfway bought into it, and I wish the villain had been more developed, but it was still interesting and exciting to read about.

In the end, I could have swallowed the far-fetched plot elements, but the characters were too hollow for the book to work for me. They’re like two detailed black-and-white drawings that haven’t been colored in, bringing them fully to life. I liked Celia, but she remained too remote. The same goes for Roy, although I liked him somewhat less. We learn quite a bit about each of them, but they’re merely surface details. In the end, I had too little idea who they were deep down, what it was that made them tick and what motivated them to act the way they did. They remained too unknowable for the story to be truly involving, and for the love story to be as effective as it might have been. In the end, the romance was nice, but not very convincing.

Undercover Mistress was still a decent read. It was almost enough to read a series book this well-written. Creighton’s storytelling is sharp and engaging. If only the characters had been developed better, this might have been a captivating story instead of merely an interesting one.