Level 7 is the diary of Officer X-127, who is assigned to stand guard at the ""Push Buttons,"" a machine devised to activate the atomic destruction of the enemy, in the country's deepest bomb shelter. Four thousand feet underground, Level 7 has been built to withstand the most devastating attack and to be self-sufficient for 500 years. Selected according to a psychological profile that assures their willingness to destroy all life on Earth, those who are sent down may never return.