Sequel to Num8ers
Possibly even darker than the first book, in a dystopian kind of way. I enjoyed it, though.
It takes place about 15-16 years after the first book and half the narration is Jem's son Adam. The other half is a new character- a girl named Sarah who keeps seeing Adam in her nightmares, even before they meet.
Overall, very interesting. Recommended, but you really need to read Num8ers first.
There will be a third book too, following Adam and Sarah and Mia a couple years after Cha0s, but I'm not loving where it looks like it's going, so I'm not sure if I'll read it.