Timing is Everything

Gwyn: Now, David and Ian, do you know what is always behind time?

David: No idea Gwyn.

Ian: I’ll buy it Gwyn. What’s the answer?

Gwyn: The back of a watch, of course!

_{Source: “A Thousand and One Riddles – With a Few Thrown In”. Victorian book of riddles published by George Routledge & Sons, London}