The first half of this novel was somewhat disjointed, plodding, and more of a testament to relationships within Sigma than anything else...but, as I should have known, Rollins does a great job bringing plot elements together (approaching comet, crashed satellite, North Korean gang elements, historical aspects of Ghengis Kahn, etc.), incorporating necessary characters (Gray, Monk, Kowalski, Seichan, Jada, Duncan, Painter, etc.), and having them all come together in Russia at the world's largest fresh-water lake to tie everything up neatly. The concept of averting world disaster by using their knowledge of dark energy with respect to the approaching comet made for a real nail-biting ending. Rollins has put forth another great read.