*See previous summary of series for character list
This book picks up a few months after The Immortal Rules, with Allie following her blood tie to Kanin to find him and rescue him from Sarren. She begins to feel two pulls on the tie, and in following one ends up finding Jackel rather than Kanin. He convinces her to join forces with him since they both know they wouldn't be able to defeat Sarren alone.
The queen of the city they're in (Azura) tells them not only do they need to defeat Sarren for Kanin, but because Sarren is in search of the research the scientists were doing but doesn't know why, and recently passed near her city looking for it in the subway tunnels of DC.
Jackel tells Allie if she will help him find the lab in the tunnels (since Azura knows where it is), he will help her defeat Sarren. When Allie asks why Jackel wants to find that lab, he tells her it's so he can get the research for himself to begin working on finding a cure to Rabidism, therefore meaning he can finally raise up his vampire raider army by being able to turn them without them becoming rabid.
Allie reluctantly agrees and they go in search of the lab, but after fighting their way through a huge horde of rabids to get to it, they see that Sarren found it and has taken the vials of blood and research.
They now go to New Covington to rescue Kanin, and so Jackel can get the vials and research from Sarren. New Covington is now like a disaster area, with people running through the streets going crazy, attacking anything in sight and clawing at their faces. While they wonder what is happening the realization come to them. Here's a quote from the book that explains it best:
"And now, Red Lung had emerged again, in New Covington. Or a version of it had, anyway. Jackal and I exchanged a grave look, no doubt both thinking the same thing. This was what Sarren wanted, why he'd taken the virus samples. Somehow, he'd created another strain of the plague that had destroyed most of the world, and he'd unleashed it on New Covington."
To avoid the sick people, they go into an abandoned underground building and there they find Zeke, who had come looking for Allie after she left Eden. He has become a leader of the small group of people who aren't sick that are left in the city and they have been hiding out ever since.
Realizing they will be unable to get through the gates of the Inner City since Salazar has sealed them off, they try to figure out a way to get in throught the sewers, and Allie suggests they ask for help from the people who know the sewers best, the Mole Men.
A Mole man living in the sewers tells them he will help them find their way out of the sewers to get to the palace in exchange for Zeke's crossbow, perfect for killing vampires. They agree and he helps them find the exit that comes out within the Inner City.
They reach the palace and speak with Salazar, but it turns out that Sarren is there too and has been acting like an ally to the prince. They explain of Sarren being the one to release the new plague into the city. Now that he's been outed, he attacks Salazar and escapes and Jackel, Allie, and Zeke are able to rescue Kanin by promising to bring Sarren back to Salazar with the cure to this plague.
They now go on a hunt for Sarren, and to ensure that they don't just leave the city and escape, Salazar has injected Kanin with this new strain of plague, which slowly kills vampires as well as humans and they only have 72 hours to find Sarren in the city and bring him back to the prince before Kanin dies.
Zeke receives a call on his walkie talkie that the human group is in trouble and the Mole Men are attacking them. When Zeke, Allie, and Kanin say they are going to save the humans first, Jackel gets mad that they feel humans are as important as getting to Sarren and leaves them.
They arrive too late and find that most of the humans have been killed. Zeke has also been bitten by a crazed human in the process of trying to get back to the humans and is slowly getting very sick. They are almost to the hospital where they think Sarren is but Zeke can't continue and they leave him hidden in a van near the hospital while they go to fight.
When they find Sarren they are about to fight him but bright lights go on and Jackel attacks them from behind. Sarren grabs Kanin and throws him in a cage and ties Allie down to a lab table to torture her and show her what types of "experiments" the humans had done on him when Kanin turned him in when Rabidism started. He also explains that he's not looking for a cure to Rabidism by taking the scientist's research, but that he means to modify the virus and release it all over in a similar way to what he did in New Covington so the world can "start over" and all rabids, humans, and vampires will be extinguished.
Jackel then cuts Allie loose while Sarren isn't looking and together they attack Sarren but he almost defeats them until Zeke shows back up and shoots Sarren. Allie then cuts off Sarren's arm and he runs away. When Allie asks how Zeke managed to make it there, he tells her he feels fine now and explains that he had been a willing guinea pig to the scientists in Eden who were looking for a cure and they had given him a vaccine that apparently works, so the cure is in his blood.
Zeke lets Allie draw his blood and inject it into Kanin and it works to cure Kanin also, so they know for sure now that the cure in Zeke's blood works. They draw more of Zeke's blood into a vial to give to Salazar and Salazar accepts it even though they tell him Sarren is gone.
They spend the night in Salazar's palace and make plans to go to Eden now to let the scientists there know the cure worked, but Stick, now Salazar's pet, lures Zeke out of the palace with the promise of knowing where Sarren is so Zeke can kill him, but instead leads Zeke into a trap so Sarren can capture him.
Allie goes back to the hospital, knowing Sarren wants her to find him, but finds only blood and a recording of Zeke being tortured and Sarren asking him how he survived the virus, knowing Zeke must have found a cure, since Jackel had told him how sick Zeke was when he was acting like a traitor.
Zeke tries to resist but Sarren tortures him so badly that Zeke finally reveals the truth and Sarren heads to Eden to try to stop the scientists from getting any farther with their cure which would ruin his plans of killing the world. The recording cuts off with Allie thinking Zeke is dead. Allie, Kanin, and Jackel head towards Eden to kill Sarren and warn Eden of Sarren's plans.
End of Book 2