James J. Kelly, a former soldier in the American military, finds out that the American and Soviet governments are about to conduct tests of a new kind of neutron bomb called the "model b" or the nC, which will kill every living thing on the planet, leaving it uninhabitable for centuries. The American generals know the cataclysmic effects of conducting these tests but they acquiesce to the tests anyway, ignoring a report provided to the National Security Council which predicts the end of the world if six or more nCs are simultaneously exploded. Mistakenly assured that the Soviets would not explode reciprocating nCs, the generals are unwittingly about to destroy the whole world.