It is 498 years since the two Foundations came into existence - half-way through the Interregnum planned by Hari Seldon. The Second Foundation has once more successfully concealed its existence so that the laws of psychohistory can operate to usher in a new Empire ruled by the mental sciences.
When the First Foundation was conquered by a force Seldon had not foreseen - the overwhelming power of a single individual, a mutant called the Mule - the second Foundation was forced to reveal its existence and, infinitely worse, a portion of its power.
