“That’s bad!” Mr. Swift murmured, as he looked toward the part of the works where his son had his own private place for experiments and tests. A pall of smoke hung over it.

While Tom’s father and his friends are rushing to do what they can to rescue the young inventor, something about the hero of this story will be told to new readers of this series.

Tom Swift lived with his father in their beautiful home in Shopton, a town in one of our Eastern states. Tom’s mother had been dead some years, and Mrs. Baggert was the housekeeper, and a veritable second mother to the young inventor.

For Tom was an inventor, like his father, and in the first volume of this series, entitled “Tom Swift and His Motorcycle,” it is related how he bought Mr. Damon’s smashed machine, improved it, and turned it into one of the speediest things on the road.

Tom had many adventures while doing this, as he had while in his motor boat, his sky racer and other machines by which he ate up time and distance as set forth in the various volumes. It was on one of Tom’s journeys to unknown lands in a machine of the air that he had brought back Koku, one of a race of giants, and since then the big fellow had faithfully served Tom Swift.

Just before the present tale opens, Tom, as related in the volume just preceding this, entitled “Tom Swift and His Airline Express,” had perfected an aeroplane that could pick up a coach, something like a Pullman car, and bear it quickly through space. Tom established an airline service across the United States, dividing the journey into several laps, picking up different coaches in Chicago, Denver, and San Francisco.

He succeeded after battling with unscrupulous men who sought to hamper his efforts, and he also succeeded against a financial handicap. When almost doomed to failure, however, Tom saved a millionaire, Jason Jacks, from death in a runaway accident, and out of gratitude Mr. Jacks loaned Tom the money to complete and perfect his Airline Express.

The odd machine, an airship with a detachable car, met with favor, and from the proceeds of it Tom and his father gained large sums. Then, running true to form, the young inventor looked for a new world to conquer and turned his attention to a machine he hoped would move rapidly over the land, like a racing automobile, in the air, like an aeroplane, and on the water, like a motor boat.

Tom had practically completed his plans, and work on the new apparatus was well under way when the visit of Mr. Burch and Mr. Trace occurred, resulting in Mr. Swift’s rather rash wager.

“I guess I’m likely to lose before Tom even has a chance to try,” mused Mr. Swift as he hurried on toward his son’s private workshop. “If his place is blown up, he may be blown up with it!”