Summary & Review of Under Their Skin by Margaret Peterson Haddix

Under Their Skin by Margaret Peterson Haddix.  January 5, 2016.  Simon & Schuster Books for Young Readers.  320 pages.  Ages 8-12.

Summary
Twelve-year old twins Nick and Eryn have had a pretty uneventful childhood.  Though their parents divorced when they were young, it was very amicable and they have been able to remain friends and continue to co-parent together. 

Then one morning their mother announces she is getting married.  Though the twins are only a little surprised; after all their mother and Michael have been dating for a couple of years.  They like Michael, so at first they are okay with the idea, until their mom tells them they are going to move into a new house.  Then she drops a real bombshell:  Michael has two children of his own, Ava and Jackson, that they have never even heard about, much less met, before now.  Even stranger, their mom tells them that they will never meet their new step-siblings, even though they will share a house, just not at the same time.

Nick and Eryn and very perplexed by this strange arrangement, and become intensely curious about Ava and Jackson.  How old are they?  What do they look like?  What kind of things do they like to do?  Why are their parents so determined that they should not meet?  None of it makes any sense.  The twins take advantage of an unexpected snow day resulting in them being home alone to break into their step-siblings locked bedrooms, finding them almost eerily similar to their own.  In one, they find the address to Ava and Jackson's home with their mother. 

Nick and Eryn sneak over to the house in hopes of seeing and possibly meeting Ava and Jackson.  What they end up seeing leaves them shocked and feeling frightened and betrayed.  As they search for answers, what they find turns their world upside down. 

My Thoughts
This is the first of a 2-part sci-fi mystery that is very fast-paced and starts with what seems to be a typical family, but the mystery develops quickly, with some very surprising discoveries.  This book is written in similar style to the author's previous works, and will not disappoint fans of her other books.  I would recommend this for ages 10-12 primarily, though some younger and older readers might enjoy it as well, and those who are fans of science fiction or mystery fans who are open to trying sci-fi.

On thing I found interesting about the story was that an important scene was set in Mammoth Cave National Park, which is in my home state.  What was even more interesting to me was the story behind how the author chose that particular setting.  As it turns out, the author had been invited to visit two elementary schools in the nearby city of Bowling Green (where my daughter's college happens to be), and her visit coincided with a sinkhole opening up under the Corvette Museum in Bowling Green and swallowing up eight classic Corvettes.  This drew her attention to the abundance of caves and sinkholes in the area, including Mammoth cave, and led to her using it in her book. 

Other Books by This Author
Margaret Peterson Haddix has written many popular books for middle grade and young adult readers, both stand alone stories as well as the well-known Missing and Shadow Children series. 

The story of Under Their Skin is concluded in the sequel, In Over Their Heads.