Revenge is acid on the scabs on personal failure.

Kessler wants revenge, and he has Manny and Ava in his sights.

The rules are tough on everyone, but even more so on Manny and Ava as they try to remember why they are helping.

Can the two of them help their fellow humans when the focus of the base is on killing machines?

Gorilladillos, Mandrillion, and the Damned Monkeys are the latest problems for our warriors out in the ZOO. Are you ready for more nightmares?. 

The ZOO finds horribly new and dangerous ways to attack Ava and the team. Can Ava, Manny, and the others adapt fast enough to stay alive?