Main character Jack Ryan, now an analyst for the Central Intelligence Agency, takes part in the extraction of a Soviet defector who knows of a KGB plot to kill the pontiff.

[1] In 1982, Pope John Paul II privately issues a letter to the communist Polish government, stating that he will resign from the papacy and return to his hometown unless they cease their repression of counterrevolutionary movements in Poland, particularly the Solidarity trade union.

Known only by the number 15-8-82-666 for security reasons, the assassin is then selected as a Turk Muslim (understood to be Mehmet Ali Ağca), who would then be eliminated by Bulgarian KDS officer Boris Strokov afterwards for deniability.

Ryan is later sent to St. Peter's Square in Vatican City to accompany the British SIS officers on the ground to ascertain how the attack on the Pope will play out, as well as to try capturing the shooter.

In a mixed review, Publishers Weekly derided the lack of suspense, which is "a disappointment when other writers (Forsyth in Day of the Jackal, for one) have shown that there can be enough tension in a fated-to-fail assassination plot to give a stroke to a yoga master".

[3] Conversely, the book was praised for its "believable and encyclopedic" plot; Publishers Weekly remarked: "It's utterly fascinating to read Clancy's playing out of that likely scenario—is there a writer in the world who brings so much verisimilitude to scenes both high (Politburo meetings) and low (details of spy craft and everyday Soviet life)?