In preparation for presenting his new airship to the United States Government, Tom has invited a Lieutenant Marbury, from the Navy, to review his ship.

Tom creates two new inventions for this story: a huge airship for military use, and a method of dealing with recoil on the weapons to be used.

Tom hoped to sell this to the United States government, with an eye on the hostilities occurring in Europe at the time of the story.

Secondary to the airship, Tom needs to conceive of a way to neutralize recoil from the guns which he plans to mount: two 4-inch cannon, and several unspecified machine-guns.

When fired, the cannon would generate enough recoil to rip the ship apart, but Tom is inspired by Ned's observation of how an automatic door closer operates.