2.75 would be my technical rating. This sequel was little slower going than the first book. Eli's family is recovering from being gone for six years underground (literally) through forced imprisonment by their father. It would be more than natural for multiple characters to have trust issues as well as other coping needs. Unfortunately, those were the parts that seemed to drag out for me. The family (mostly Eli and his mom) feel the need to continue to keep the family inside their new house because they aren't sure who to true and they have obviously also become the most popular news story out in the real world. Staying inside and hearing a lot of what was going on inside Eli's head became a little boring at times and while this was a quick read, I think the middle was pretty slow going. 
 Like in the first book, The Compound, I enjoyed the premise of the story, but had a hard time with some of the science fiction aspects (I won't go into detail so I don't spoil anyone) and also thought the slow character development could have used some more exciting events. Not a bad duo-logy, but definitely for middle grade.