It's an adventurous five-book young adult fiction series about survival and self discovery. Inspired by the dark timelessness and unpredictable vast landscape of Dartmoor National Park in Southern England, a group of school children on a hiking expedition unleash an unknown power, transporting them through time, to a world beyond anything they have experienced. Cut off from the adult world in unfamiliar environments, the series chronicles their adventures as they desperately try to return home.

Each book in the series involves travel to a different time, where the group has to survive using skills and knowledge they have gained from their old life. On a journey from the prehistoric age of the Neanderthals to the 14th century Black Death; from the Convict ships of the 18th century to the more recent discoveries of Marie Curie, the group are drawn back to the strange stones of Dartmoor.

In the final book, Tregarthur’s Legacy, the remaining members of the group are caught up in a never ending war that is raging across a WWI stricken France. In this explosion of past events, Mellanby has yet again delivered a powerful story with themes pertinent to young adults intertwined with mystery, historical fact and adventure that has delighted his growing readership.

Can Alvin and Jenna survive? Will they save their companions? Why does Alice Tregarthur want them all to die? Is this just about her or is there a larger force involved, something dark and timeless from the moor?