It started very slowly, very naturally, as you would expect when you're waiting after midnight for a son or daughter who is out too late. At first, they are just overdue. Then after an hour or so, when they really are late, you start making mental lectures to them, until the second hour, and then the third has passed. Then, all very slowly, very naturally, you discover you have stopped making mental lectures, because you aren't peeved or impatient any longer. You're just scared...