"14," by Peter Clines

Peter Clines novel, "14," tells the story of seven initially clueless building tenants who discover that their building is a machine disguised as an apartment building and they are just part of the disguise. The machine has been designed and built to protect the world from alien monsters, who hover just out of dimension, waiting to eat everyone. It sounds stupid, and on reflection, it is, but there's fun to be had while reading the 446-page thriller.