***SPOILERS**** Eerily similar to the 2013 Boston Marathon bombing some 54 years later this "Naked City" episode has to do with a disgruntled NYC Park's employee Alton Marshak who felt he was given a raw dead, canned from his job of some 20 years, and now was going to get even with those who screwed him by blowing up City Hall. And do it at the end of a ticker tape parade for Olympic hero Mason "Mace" Conway at the end of the biggest ticker tape parade since VJ Day.
It's never fully explained just why Marshak had it in for the city and why he was fired, he did a few bad things is what he said, but his reasons were enough for him to end up possibly killing dozens of people including the mayor and members of the city consul as well as "Mace" and his blind, from a car accident, and lovely wife Arline.
As you would have expected, unlike in the 2013 Boston Maraton bombing, the local police got the drop on Marshak and prevent his dream of revenge from coming true. Not due to any excellent police work on their part but because of Marshak's big mouth that he just couldn't keep shut and blabbed out his intentions more or less to anyone close to him in the parade march.
It was detective James "Jimmy" Hallaron who save the day as well as dozens of lives by putting his life on the line by disposing the make shift bomb that Marshak planned to cause death and destruction at the end of the parade route at City Hall. And for all that all Jimmy got was a pat on the back, not a ticker tape parade in his honor, and a "keep up the good work" from his superiors who in fact owed their lives as well as limbs, if they survived the explosion, to him.