An eighteen-year-old boy goes with his parents on a trip to the west coast of Ireland. There he becomes involved with a local wildlife station where biologists are studying the causes of variations amongst species of birds. This research has centred on an off-shore island where there are the ruins of the cells in which hermits in the Dark Ages had to come to live and survive. He also becomes a chance witness of terrorist gun-running activity. He tries to imagine how these ways of life might be connected.
He returns to an English university where he has intended to study biology or literature. But he finds neither of these disciplines is much concerned with wider experience. After a year he returns on his own to the west coast of Ireland to try to discover what, if anything, were those old hermits looking for? Is it possible that human nature, like a species of bird, might evolve and change?
On his first visit to Ireland he had fallen in love with the glimpse of a young girl who, it had seemed, might be involved with the gun runners. Together he and she now go to stay on the deserted island. It becomes possible to imagine this island as the mythical Garden of the Hesperides where, at the extreme limits of the western world, there was thought to be the Tree of Life with its golden apples.
