It’s a sequel to “Kane and Abel” and “The Prodigal Daughter” by the same author. 

          At the end of The Prodigal Daughter, Florentyna Kane is elected President – the first woman President of the United States.
At 7.30 one evening the FBI learn of a plot to kill her – the 1572nd threat of the year. An hour later five people know all the details. By 9.30 four of them are dead. FBI agent Mark Andrews alone knows when. He also knows that a senator is involved. He has six days to learn where – and how. Six days to prevent the certain death of the President.