A British traitor returns to his homeland and must be found before his former colleagues, seeking vengeance for his past betrayals, go in search of his whereabouts.

Bodie and Doyle are assigned to protect a foreign official who is on a secret visit to Britain. But already possible enemy assassins appear to know his - and CI5's - every next move.

Bodie is re-acquainted with a former girlfriend when she shows up in London, and during a secret meeting with her finds himself framed for an assassination and then ultimately on the run from his own colleagues at CI5.

A dummy run that has been staged for the visit of a Middle Eastern official is found to have been recorded by a foreign student, subsequently leading CI5 to suspect a security leak.