Once a Noble Endeavor is a story about protagonist, Nicholas J. Brennan and the clever analysis and devices he uses fighting crime and terrorism. As the tale opens Nick is in Vietnam on a mission for the US Army Security Agency, a branch of military intelligence. In the first scene Nick and his boss, Specialist 5th Class John Planner are tracking an enemy agent in the wooded highlands near Pleiku. The discovery of the Viet Cong spy results in Brennan killing one adversary and his group capturing the secret operative. As the readers follow Nick into civilian life they witness Nick's police basic training, his marriage to the beautiful, brilliant and sexy Joann Termino, his police promotions and the beginning of his successful 20 year police career along with his ultimate graduation from law school. In a notable event while working as a police patrol supervisor, Nick wounds, a young psychopath and former juvenile delinquent named Steven A. Clinton in a dark alley next to a popular bar. Clinton a trigger happy young man with a long history, who carries a 12 gauge sawed off shotgun, had just fired on and seriously injured several patrons in the local tavern and taken refuge between two buildings outside. Clinton is later convicted of several felonies and sentenced to 22 years in state prison. As a police lieutenant, Nicky, as Joann sometimes calls him, becomes the commanding officer of the department intelligence unit and with the help of his squad, stops the attempted bombing on the mezzanine at the Grand Terminus Plaza rail station during an open call for children to audition for media events. Police Officer Erin Peters, Brennan's competent subordinate, shoots and kills Aaffia Khan, just before Khan detonates the explosive device. A follow up investigation reveals that Aaffia is an agent for a terrorist organization led by Bhiren al Mohammed. Unknown to the FBI Bhiren with the help of others in the UK is planning to kill a subway train full of Catholic school children in the Montague Street tunnel - a passage connecting Brooklyn and lower Manhattan. Team 1, at first frustrated with their lack of progress is surprised when Nick, based perhaps on beginner's luck, finds a substantial lead to pursue. The thread runs through England, Canada and finally back to New York. The messages between the conspirators is encrypted in a seemingly unbreakable code that Nicky, with the help of his history professor wife, and using the old battlefield codes from Vietnam, is able to break at the last moment. Brennan pursues al Mohammed through the subway tunnel in a running gun battle which finally ends in Battery Park when Nick kills Bhiren al Mohammed who is firing in desperation at the tourists witnessing the gunfight. Meanwhile, unknown to Nick and Joann, Steven Clinton, after his release from prison, is searching computer data bases in an effort to locate the Brennans to gain his revenge. He finally discovers their vacation home in Great Barrington, Massachusetts and violently invades the house while Joann and little Elizabeth Brennan are waiting for Nick to arrive.