A cold breaking dawn by the River Thames and a tugboat operator sees a man on the bank being beaten by two other men. After going to him, the victim's last words to him before dying are 'the eagle will fall.' In the dead man's pocket is the name of Alex Swan, former MI5 officer, and now with the Ministry of Defence Services Investigations Department. It's 1969, and there is a race to the Moon. Simon and Garfunkel are on the radio and in the bookshops...