At St Mary's Institute of Historical Research, the historians don't just study the past, they revisit it. Behind the strait-laced façade of a conventional academic institution, the secret of time travel has been discovered and is being used for ground-breaking and daring historical research. The series takes the reader on a rollercoaster ride through history: from the destruction of Pompeii to the trenches of the First World War; from the Great Fire of London to the burning of the library at Alexandria; from Bronze Age Troy to the time of the dinosaurs... Meanwhile, within at St Mary's itself, there are power struggles, romances and intrigues worthy of a book in themselves.