There's nothing truly original about The Passage. It's tome of a read, broken up into distinctly separate stories of what is essentially a post-apocalyptic disaster story. Yet it's this that somehow makes it stand out from the crowd.
The first book is the classic science gone wrong. A well meaning scientist test a virus to extend human life which backfires and destroys humanity. It's what makes up countless science fiction stories. The details are impressive; the dreams and different styles of writing and multiple perspectives. It keeps you intrigued in what is an otherwise overdone plot line. The death-row inmates as test subjects was a twisted touch that seemed scarily possible. That was part of the intrigue of this novel; you could suspend disbelief easily, and see this happening.
Post apocalypse we move forward in time to where humanity's last colony is attempting to survive. It's very Attack on Titan meets World War Z, and the characters were all individual enough for you care what happened.
It could have been more concisely delivered, and the stories are not new; I just haven't ever read them in the same over-arching plot line. You are in for the long-haul with this one, but if you're okay with that, it's worth a go.