The entire story, set in the early Sixties, is narrated as a flashback by Ralph, a retired mailman. When Stanley and Charlie, two bored postal clerks working in a large Post Office in Downtown Manhattan, united by the same passion for booze and gambling, cast their eyes on Larry, a naïve mailman, to make one of their frequent bets, they can hardly imagine that their innocent pastime would have so many devastating consequences.
As the preparations are underway, Larry's increasing involvement in the fake mission triggers a series of events attracting the interest of more and more people, including agents of the CIA. Driven by different motivations, even foreign governments become involved in the absurd affair.
Only Larry seems to be aware of the fact that those written pieces of paper, sheltered by envelopes of all colors and sizes, hold an incredible secret that goes beyond any human perception. When he tries to explain this fact to his colleagues at the Post Office, he becomes the object of further derision. Ultimately, when the letters become the real protagonists of the story, the Reader will discover that Larry was right.