A coach delay and the driver's decision to miss a stop triggered a six hour absence that involved several police forces and put the family through an evening of torment.
In that situation what you want to do more than anything is feel that you are doing something. The urge to jump into a car and drive to Exeter and go around looking for her is a difficult one to resist because it meets the overpowering need to be active.
But when that isn't practical there turned out to be another answer and one that might just surprise those people that believe social networking is a pointless vanity exercise.
After being given the green light by the police I called for help in the search for my mother-in-law on Twitter.
I watched as my call for help in locating her went ever wider and it wasn't long before someone contacted me prepared to go to the coach station and look for her. That was the very thing I wanted to do myself but in the absence of getting there a Twitter contact was going to go and do it for me.
Just put yourself in their shoes for a minute. Here is someone busy minding their own business who sees the call for help and responds. She puts to one side her plans for the evening and goes to the coach station, alerts security there and then goes on a hunt round the pedestrianised shopping area to see if there are any signs of my aged relative there.
I didn't offer a reward, it was a simple call for help and it was answered. The support and the goodwill, with people offering ideas and assistance, was staggering. It even surprised the police when I mentioned it to them when they came to get further details of my missing mother-in-law.
In the end she was found and the saga had a happy ending but of course there are going to be plenty of lessons that this experience has taught her family.
But there is another lesson here about the power of social networking. Twitter proved that it is a way to reach out to people who care, are prepared to give up their time and energy and it showed that when you need help there are new ways of getting support that deserve to be taken seriously.
Twitter might not have actually found her but it provided eyes that I couldn't have in the right places and it provided support in a time of trouble that you just wouldn't believe. Thank you to all those who tried to help.