Simply, just that -fascinating. Written in the first person, as the novel progresses, you can sense the deep anguish the protagonist feels without her ever saying it in as many words. It goes backwards and forwards, interweaving the present with the past, and the characters come alive through her mind’s eye as she recollects incidents that lead up to the present.
Right from school times to the end of their days, the lives of the protagonist and two others are intertwined. Though all move off in different directions, they are together again as one of them is nearing her end. How she brings the other two together, and what happens to them is the main plot. It also subtly raises the ethical issues of cloning and the real status of the clones themselves. The hopelessness of the situation really hits you hard.
I must admit that the novel did sag in a few places. But once the drift emerged somewhere midway, then it became unputdownable.
I am wary of new(for me) authors, having burnt my fingers quite a few times in that area. But this one was worth all that.