When twin brothers Sandy and Dennys are caught up in one of their father's experiments, they find themselves in a strange desert landed peopled by humans only four feet tall. They meet other strange creatures - the deceptively beautiful nephilim, the winged seraphim and, of course, the unicorn.
As the brothers are drawn into a battle between good and evil, they gradually realise just where in time they are and the terrible danger threatening the world. Perhaps their presence is not an accident after all.