This continues the events of the first book, THE STRAIN. It wisely concentrates more on the old vampire hunter, Abraham Setrakian, rather than Eph Goodweather, who is sort of a one-note character about wanting to protect his son from how vampire ex-wife. We learn what the "Master" wants and why he wants to destroy the other Ancients. And we learn who that worm infested vampire heart that Setrakian kept for decades belonged to. Plus, a few of the villainous human characters get what they deserve.
This is a quick, enjoyable read. I didn't like it quite as much as the first novel in the trilogy but I did like how it finished, with the beginnings of an "end of the world" type scenario that will completely change the tone for the first book. Recommended.