Now I didn't plan this, but The Children will be a continuation of AATU. It will be on hold until I finish AATU and the second spin-off book called Boys Will Be Bugs featuring Bugs after Alistair and other people go missing. 

Timeline:

Alistair and the Unknown: #1

Alistair meets Matt and accidentally finds out his secret. He and Matt are forced to flee and find themselves in unfamiliar territory. 

Boys Will be Bugs: #2 

Through the perspective of Bugs, Eddie, and Bug's second-best friend Corey. Bugs meet Corey's best friend from England, Eddie Allen Hart. Even more mysterious things happen when Alistair is supposedly "taken" as Bugs puts it. Most of the town thinks he is crazy except for Corey and Eddie, who help him connect crucial clues to find Alistair and Matt and (spoilers). *Poly*

The Children: #3 

Raven and Luca stumble upon each other on accident but neither now that one another is crucial to each other's survival. Raven and Luca have been trapped in this alternative universe for years until they find a possible way to escape.

All eight are tied together in some way.