On June 1st 1963 Donald Bailey set out on a hiking tour. For twelve days it was mountain and lakes, rivers and fells, healthy exercise and the magic of a starlit campfire. On the thirteenth day they found a cave and decided to explore. A rock fall cut off the entrance and they searched desperately for another way out. Exhausted and battered, they finally scrambled through a small shaft into a strangely changed countryside which was familiar, yet not familiar.
From a cottager who fed them and tended their wounds they learnt that somehow they were back in the days of the Civil War. Roundheads and Cavaliers battled desperately across the country and they found themselves involved in the bitter struggle for power.
Unwittingly they gave information to a Roundhead spy, which resulted in the death of a Cavalier Commander. He returns from the dead in monstrous form, trying to exact a terrible vengeance on the bewildered pair who are desperately seeking to return to their own time.