'The known universe is home to countless trillions of lives, all interweaving with each other and affecting the line of history. When someone makes a decision, no matter how significant or seemingly irrelevant, they cause unknown effects throughout the ages ...
Perhaps other, unreachable, factors at are play too: does the universe have a destiny? Are we all predetermined to follow a particular path? Do we reap what we sow or is it a case of what will be will be? Are coincidences really just that, or do we miss their deeper meanings?
Everywhere he looks, the Doctor sees the same patterns - the same events, decisions and actions cropping up again and again. Look at the bigger picture, however, and maybe - just maybe - you'll see how the universe works. How the universe lives...
But, as the Doctor and his companions discover, are these patterns really there? Or do we, by the very nature of seeing them, define them?'
Source: drwhoguide.com (http://www.drwhoguide.com/whotrip26.htm). Sighted: 20/5/11