Set in the year 2052, it depicts an authoritarian England divided into two distinct societies: the modern, overpopulated "Conurbs" and the aristocratic, rarefied "County".

The story follows a young Conurban orphan named Rob as he experiences life in both worlds, uncovering truths and choosing sides in the process.

[3] Following the suspicious death of his father, 13-year-old Rob Randall is sent to a State boarding school, where harsh disciplinary measures and hazing by seniors soon make life intolerable.

The Barrier proves much less of a challenge than popular rumour suggests, and, finding a spot at which he is able to dig a gap underneath, Rob crosses over into the County.

So, declaring him a relative raised in Nepal and playing out his supposed arrival from the nearest station, Rob is inducted into the Gifford family.

These skills are put to the test when the Giffords hold a garden party and Rob is questioned by Sir Percy Gregory and an elderly man named Harcourt.

Several months pass and Rob becomes increasingly confident and assured of his position, even going so far as to win third place in the archery contest of the year, beating Mike who comes in eleventh.

Mike brings Rob to a gathering held by a senior boy named Daniel Penfold, where a heated discussion on both the failings and the merits of the current social system ensues.

Ashamed, Rob prepares to ride out to meet a band of vigilantes countering the insurrection, but Mrs Gifford asks him to stay as all the men of the house have already ridden out.

Disturbingly, Sir Percy tells Rob of what is to be done with Mike if he is found: a certain surgical procedure on the brain which renders the subject docile and obedient.

Mrs Gifford tells him that she is aware of Mike's visit the night previous – having again noted the absence of some household articles, such as food and clothing – and again rebukes Rob for not doing what she feels would have been the right thing.

Rob also realises that he had almost bought into the groupthink himself by assimilating into the gentry with such determination that he had forgotten his Conurban past, even taking up the offer to join the Guardians.

He makes a decision: either he can remain in the place he has won in County society, now in perfect safety, or he can join the movement which has fled to the Conurbs and struggle alongside Mike in liberating the masses.