The book is by Mary Pope Osborne.It is about Jack and Annie going to Antarctica. They get on a tour bus with adults and say they are adults, but they are really kids. The first stop  the tour bus makes is for a helicopter ride. Jack and Annie get on the helicopter and fly over a volcano.  When they land on the other side of the volcano, Jack and Annie take off the masks they were wearing on the helicopter ride. This is where Nancy, the tour guide, discovers that they are kids. Nancy then puts Jack and Annie in a tent because they are kids and she asks them to stay there while she catches up with the rest of the group. Annie leaves the tent to take pictures. Jack goes to get Annie. Next the ground begins to shake and they both fall throuhg the snow onto an icy ledge. The ledge then breaks! What will happen to Jack and Annie? Why is there a volcano in Antartica? Read this book to find out!

I'd suggest this book to anyone below the age of 12 who likes adventure. I give this book a 4 out of 5 stars.