Jack Chabert 
Mystery of the Map (Poptropica Book 1) [EPUB ebook] 

New York Times Bestseller Based on a concept by Wimpy Kid author Jeff Kinney comes Poptropica, a brand-new graphic novel adventure series by Jack Chabert and Kory Merritt. In Mystery of the Map, Oliver, Mya, and Jorge take a ride in a hot-air balloon, only to crash-land on an unknown island filled with extinct animals and a horde of angry Vikings. Welcome to Poptropica, an uncharted group of islands whose existence is hidden from the rest of the world. As the three friends embark on a perilous search for a way home, they quickly discover the shocking reason they were brought theresomething that threatens the very existence of Poptropica and their ability to ever make it off the island!