Those responsible for governing and protecting society finally get it wrong, and much of mankind is set to perish in the ensuing nuclear strikes.
A small group of tourists in the Scottish Highlands reach the perceived safety of a long-disused railway tunnel.
Blinding light from the nearest explosion briefly illuminates the cavernous space within the mountain. After witnessing the light there is total darkness.
Relief is followed by anxiety, which is rapidly usurped by fear. What next?
It becomes clear they are not the only inhabitants of the tunnel.
A brief update: 23 Oct 2019,
I have now completed the first full draft of this story
and it has grown from an idea to an ongoing project of 66k words.