I very much enjoyed a previous book ('Remix') by this author, so this seemed like a good bet and I wasn't disappointed. The only difficult part is the initial premise: that a scientist has developed a method of cloning which produces a robotic-like copy under the control of the original, intended for military use, and decides his first human test subject will be his secretary Beth, whereupon things go slightly wrong - the copy is fully autonomous. Yeah, right. But the author addresses our scepticism: the process has already been extensively tested on animal subjects with the expected results. But why would the secretary agree to it? Because she's a meek little doormat. On the whole, it doesn't require much effort to go along with this.
Once you get past this point, the plot flows along in a totally logical and believable way. The scientist's boss sets out with a team of hitmen to capture, test and ultimately kill the replica, and the story follows her attempts to escape this fate. Because we see both sides, both hunters and prey, the tension is built up beautifully. There are narrow escapes and things going horribly wrong for both. The people the replica (Beth Two) meets all behave in credible ways - the officious security people who move her on, the doctor who disbelieves her story but doesn't try to hinder her, the friendly homeless people, the slight acquaintance she turns to in desperation who is so baby-befuddled that she asks no questions.
In the previous book, the characters had a certain eccentric charm, but the main characters here are less appealing. Beth One is - well, a doormat, and Beth Two, although she turns out to be moderately resourceful, is just a doormat scraping by in difficult circumstances, and I never found her very likeable. As for the male protagonist, Nick - look, I know the story is partly about his redemption from selfishness and arrogance, but I honestly don't see him being any different from Beth's obnoxious previous boyfriend. He hits on the woman he's supposed to be protecting when she's vulnerable, while simultaneously planning to kill her doppelganger. Yes, yes, I know he loves his son, and he's loyal to his friend, blah, blah, but a selfish jerk is still a selfish jerk. The other characters are better. I liked the Polish friend, and I loved the doctor caught up in the middle of a potentially lethal situation, spluttering in outrage - you just can't do that, this is Britain, we don't do things like that here! And the oily and cold-blooded boss is totally believable.
This is a well crafted book, and one of the most tightly plotted I've ever read. It's a real page turner almost right from the start, and a thoroughly enjoyable read.