HistoryBuff.com on The Plot to burn NY:
It was an incredible scheme. When finalized, New York City was their target and the plot was thus:. One group was to be responsible for setting off a series of fires as a diversion while another group was to seize Federal buildings and municipal offices, still another to take control of the police department, and yet another to free prisoners from Fort Lafayette and throw the Army Commander in New York, Major General John Adams Dix, into a dungeon. By sunset a Confederate flag would surely fly over New York City. This would surely be a coup for the Confederacy!
About the time the plot was finalized, Richmond learned from its spies that Washington was beginning to obtain bits and pieces of the plan to capture the North. It was then decided that, since everything but the date had been formalized, no more messages would be sent by runners. It was further decided that for two reasons carrying out the plot would wait. One reason was to “lay low” to give Washington the impression that the plot had died, and, two, the most opportune time to best capture the North off guard would be soon after another Union victory. Since Southern newspapers could still freely travel to Canada, members were instructed to keep reading the Richmond newspaper for an editorial advising that a “Northern city” should be burned in retaliation. (It is not known just how it was accomplished, but the same editorial also appeared in the New York Times a few days later!) At that time they were to congregate in New York’s St. Dennis Hotel and begin to put the plot in motion.