Nicholas Fisk

Great Aunt Emma is no ordinary lady. But why is she so strange? Why have Mum and Dad never mentioned her before - after all, she is supposed to be Granny's sister, isn't she? Soon Tim and Beth start noticing more and more odd things.

A teenager in the late 21st century discovers a way to travel in time as a way to escape the dystopian world he inhabits, only to learn that time travel introduces dangers of its own.