Trapped in the wrong time, Alvin and Jenna's only hope lies with Miss Tregarthur's crystal. But can they follow her in an age of horses and steam trains? Even if they do find her, the crystal is failing and the answers may not be close to home. As they start to uncover the full horror of Miss Tregarthur's mind they realise how far she will go to control time. Will Alvin escape the future she has planned? The storm broke. The wind screamed into a gale again hurling itself across the moor, whipping up mud and stones in its path, hail burst out of the storm clouds. 'Nothing happens without the crystal.' Tregarthur's Crystal is the forth and penultimate book in the Tregarthur's Series. About this book series The Tregarthur's Series is 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 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. * * * This is Alex Mellanby's fourth novel in The Tregarthur Series. His writing has finally driven him over the edge of sense and he now exists in a shadowy realm of fiction. Whether he can save Alvin and Jenna remains uncertain and the future is much worse than the past. Join in on the conversation at facebook/tregarthurseries or visit tregarthurseries.com