The book is about two children named Larna and Aron that have a fond enjoyment for geocaching. They visit their grandmother for a portion of the summer and get teleported into the future through a magical doorway in the forest. The children go through a number of trials as they fight to help their new found friends in a battle against an evil warlock.
The book has very likeable characters (my favourite character is Uncle Roger as he puts the wellbeing of others before himself) and an interesting story arc that never lets up. You are constantly moving from one part to the next and the characters are never in one spot for very long (the book can be hard to follow at times because of this).
This book is definitely for a younger audience so I would recommend this book for children up to the age of 13. A percentage of the profits from this novel get donated to research for Motor Neurone Disease so if you want a good read for your kids and to donate to charity, this is the book for you.