I'm really wishy-washy with the rating on this one.
For every urge to give Unspeakable the preordained 'it's okay' two stars, there's a little detail that I feel deserved of four.
Things that really worked in Untraceable couldn't be used here, namely the pre-existing attraction between the mains. Revisiting or revising a previous chemistry is a lot easier than creating from scratch - we easily accept what might of been by simply being told therefore skirting the issue of showing how two people could fall for each other in the first place.
Griffin has so much detail and story to pack into the book to make it a plausible mystery/thriller that there is very little time to be devoted to things like character development which make a really convincing romantic attachment beyond the physical.
Couple that with the fact (or illusion, I couldn't really tell) that Elaina is anti-social (and in the words of our authoress, "prickly") and you have a romance that is very tough feed. Troy's playboy past only adds to this dilemma. Why her, why now? We don't really know.
But there are some kudos to be given out...mostly that Griffin managed (really by the skin of her teeth) to write a heroine that was more accomplished than our hero, in the very traditional sense. Elaina is well educated and well trained, and to be shooting for a profilers spot with the FBI, highly intelligent. She comes from a somewhat jaded, but white-collar background, while Troy's past is far-less than stellar. He has money, but maybe not the cred...and especially not now that his previous best-selling true-crime novel is being shown as a simple fabrication. Troy comes off a little naive really.
Additionally, Griffin isn't afraid to get us nice and dirty (not in the way you're thinking, get your mind out of the gutter!). Elaina works hard - gets sunburned, mud caked, cut, bruised, smelly and sweaty and yet, yet, Troy still finds her attractive. Finally, some respect for women who aren't afraid to get the job done, even if that means dirt in the nails and forgoing the six-inch heals. Griffin writes women in a way that makes me say "YES!", tough women with the nuances of feminine softness (polished toes!).
Though we didn't really get cooking until 40% of the way through, it was still a good thrill.