Latin-American President Sarejo visits the United States to undergo an operation in Los Angeles. He is accompanied by his wife Isabella, vice-president Marco, Foreign Secretary Varela, General Bettraga, secret police chief Fernandez and Dr. Allermo, Sarejo's personal physician. Lieutenant Monahan's men are ready to protect the dictator against an attempt. When vice-president Marco suddenly falls and dies of a heart attack , Quincy is asked by the State Department to examine his death. The forensic doctor can find no signs of a heart attack. The cause of death remains puzzling at first. After a little while another person from Sarejo's confidant circle dies under similarly mysterious circumstances. Quincy must solve the mystery, before the president comes under the knife.