Octinnia: The Adventure Begins — Rosemary J. Peel

Eight thirteen year olds, four girls and four boys from across the world, are whisked away to a strange place when they click onto an e-book entitled Octinnia. The e-book invited them to 'Live the Adventure. In Octinnia they find they must to work together to discover and solve eight quests before being allowed to return to their homes. They enter the first mysterious zone to find themselves not only back in Ancient Greece but also much changed in appearance. Their adventure has begun.