Gregor the Overlander

Collins, S.  (2004).  Gregor the overlander. New York:  Scholastic.

Gregor and his little sister Boots fall through a grate in their laundry room and land in Regalia, the Underland.  The Underland is filled with giant cockroaches, rats, flying bats, and giant spiders.  Gregor learns that the rats are holding his missing father hostage and he is part of the Prophecy of Gray and it is up to him to lead a quest to save his father and the Underland.

Book Trailer:
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The setting is an important part in this fantasy story.  The setting is in Regalia, the Underworld.  Gregor and his little sister Boots fall into this world and meet giant roaches and spiders, a flying golden bat carrying Queen Luxa, and rats with six inch incisors that are holding his father prisoner.  Gregor learns that in the Underworld he has to take a bath or his scent will be known by all the varmints and he will quickly be killed.  The people in Regalia are pale with violet eyes.  When Gregor agrees to go on the quest to find his father and to save the Underworld, he intelligently chooses to take a headlight.  The Underworld is dark and that makes the rats have a clear advantage over Gregor.  

The plot in Gregor the Overlander involves Gregor on a quest for the Prophecy of Gray which will save the Underland.  Gregor has a more personal goal which is to save his father from the rats so he and his sister Boots can return back home.  Gregor has read the prophecy and is unsure of what it means, but his determination leads the group forward through many scary encounters.  They fight rats, hunger, and illness along the way.  They finally find his father and realize there is a traitor among the group.  Gregor discovers the truth behind the prophecy and is able to free his father and is able to return to the king as a hero.  More importantly, his whole family is able to be reunited in New York.