Oliver & Daniel return to Netherworld, where they hope to meet up with Tania again and explore Estopia, a strange medieval town which they briefly saw on their last visit. But there is a time difference between the portal they use this time and the one they went through previously. As a result, they arrive just in time to see themselves leave from their last visit and narrowly avoid the embarrasing, and potentially dangerous situation, of meeting themselves. Estopia is being terrorised by an evil man who is robbing the people using an invisibility cloaking device to conceal himself. Returning home through the wrong portal by mistake, they meet their younger sister, now 9 years old, and discover that she has never had any brothers They must not only deal the evil Fagiola but also solve the mystery of why they have disappeared from the future, leaving their young sister with no brothers

Oliver & Daniel return to Netherworld, where they were previously responsible for finding a lost artifact, needed to save the strange Parallel World from extinction. Now they have another mission. They must return a small boy, who has entered this strange land by mistake, to his own world. They are told that their own existence depends on the success of their mission, but they are not told why. This time they have The Temporal Phase Shift Adjuster to help them with their difficult task, as well as the Portal Opener which they acquired on their previous mission. This enables them to open the secret gates into and out of Netherword which lead not only to different places, but also to different times. The lost boy turns out to be from the past and the boys encounter some interesting technology from a bygone age. But with this ability to travel in time, they must be careful not to change the past, and to avoid creating a time paradox when visiting the future. They do, of course, manage to do both, in this highly entertaining and light-hearted adventure, which has some unexpected twists in the story to keep the young readers entertained. Like the first book, there is a small dictionary at the end, to help them improve the readers' vocabulary, without having to ask others for assistance. It might also encourage them to acquire the habit, as their reading ability develops, of consulting a full dictionary. The Author welcomes comments and feedback and can be contacted at alan-peters.com

Oliver and Daniel are unwittingly drawn into a parallel world, from which they can escape only by finding a lost artifact, which is needed to save the strange world from extinction. Oliver, who is only 7 years old, not only has a massive task ahead of him to track down the artifact but also the responsibility for protecting his 4 year old brother, as their adventure unfolds in the strange Nether World.