Sci-Fi Wisdom of the Week

"There is a corridor...and that corridor is time. It surrounds all things and it passes through all things. You can't see it. Only sometimes. When it's dangerous...You can't enter into time, but sometimes time can try to enter into the present; break in; burst through and take things - take people. The corridor is very strong - it has to be - but sometimes, in some places, it becomes weakened like fabric, like worn fabric..."

-Sapphire explains the "enemy" in P.J. Hammond's Sapphire & Steel (first serial; first episode)