In London, Jack Ryan saves the Prince and Princess of Wales, along with their infant firstborn son, from an Irish terrorist group called Ulster Liberation Army (ULA) during a kidnapping attempt on the Mall. Sean Miller, a ULA terrorist captured by Ryan, is sentenced to life imprisonment for killing the royal driver. However, he is freed by ULA members while being transported to prison. The ULA, assisted by an African-American terrorist group, later goes after Ryan and his family, partially as an act of revenge, but primarily because they seek to reduce American support for the rival Provisional Irish Republican Army. The assassin sent to kill Ryan is intercepted before he manages to complete his task, but his expectant wife, Cathy, and daughter, Sally, are injured when Miller causes their car to crash on a freeway. They are flown by helicopter to the University of Maryland Medical Center.
After the attack on his family, Jack accepts an offer from the Central Intelligence Agency (CIA) to start working as an analyst at the agency's headquarters. Later, the Prince and Princess of Wales come to visit Ryan in America. This gives the ULA another opportunity to conduct another operation—they plan to kill Ryan and his family and kidnap the Royal Family. The attack ultimately fails: after a firefight and a flight, Ryan, his friend Robby Jackson, and the Prince, with the help of Marines and sailors from the U.S. Naval Academy and local police, manage to apprehend and subdue the terrorists. The ultimate fate of the terrorists is not stated in the book. Ryan arrives at Bethesda after the final arrest to be with Cathy for the birth of their son, who will be godparented by Robby Jackson and his wife, as well as the Prince and Princess of Wales.