Thankful to Go to Mexico

In this book a boy Oscar with his friend Santiago reach Mexico to meet his cousin because itwas her birthday. He had to act in a movie and face many problems with Santiago butsomething suspicious happens. Can Oscar and his friends find it? Some evidences prove thathe was not a human. What can it be? a mysteries creature? or anything else? The mystery isstill a mystery and mysteries don't look interesting until they are solved so go ahead purchasethis book and till the end if you want to solve and know about the mystery.