Psychological thriller set in Berlin during the Cold War, based on an actual (but little known) incident which tells of the secret tunnel under the Soviet sector which the British and Americans built in 1954 to gain access to the Russians' communication system. The protagonist, Leonard Marnham, is a 25-year-old, naive, unsophisticated English post office technician who is astonished and alarmed to find himself involved in a top-secret operation. At the same time that he loses his political innocence, Leonard experiences his sexual initiation in a clandestine affair with a German divorcee five years his senior. As his two secret worlds come together, events develop into a gruesome nightmare, building to a searing, unforgettable scene of surrealist intensity in which Leonard and his lover try to conceal evidence of a murder. Acting to save himself from a prison sentence, Leonard desperately performs an act of espionage whose ironic consequences resonate down the years to a twister of an ending. Though its plot rivals any thriller in narrative tension, this novel is also a character study of a young man coming of age in bizarre circumstances, and of differences in national character: the gentlemanly Brits, all decorum and civility; the brash, impatient Americans; the cynical Germans. McEwan's neat, tensile prose raises this book to the highest level of the genre.