What if we could travel not just through space, but through time itself? If you could travel through time, would you change the past or the future? What if you found it couldn't be changed? What price does the time traveler - and the people they are closest to - pay? This is a journey from H. G. Wells' The Time Machine through ideas like The Grandfather Paradox and The Butterfly Effect to the professional time traveler that is the ever popular Doctor...