Forth Gregor book and I'm running out of new things to say!
This is the first book of the series were we don't start out with a new prophecy. Gregor returns to the Underland this time around to visit his mom who's still being held in the hospital in Regalia. Quickly though, he gets involved in solving a mystery alongside his friend Luxa. The pair discovers that something mysterious is happening with the Underground mice colony. Headstrong Luxa immediately starts off on a quest to solve the mystery and Gregor, not wanting to have Luxa leave him behind, accompanies her. The pair will soon discover that more is happening in the Underland than anyone is aware of.
The Underland is, once again, a fun place to be. This book strays a little from Collins' typical style - ending with a cliff-hanger, which makes me thankful that I have the fifth book already waiting for me!