“But bless my porous plaster!” the queer man would exclaim in telling the story, “I never thought the contraption was going to climb trees!”

Which it did, or tried to, because Mr. Damon did not know how to manage it. The result was that the rider was injured and the motorcycle badly smashed and Tom, near whose home the accident occurred, became the owner of the machine.

How he repaired it, added some improvements, and what he did with the machine are fully set forth in the book. It was the beginning of a long friendship with Mr. Damon, and also the real start of Tom’s inventive career.

Those of you who have followed him in his successes, from his motor boat to “Tom Swift’s Chest of Secrets,”—the volume immediately preceding this one—need not be told of Tom’s activities. He had made some wonderful pieces of apparatus and had had some startling adventures. In some of these his father and Mr. Damon had shared. So, also, had Ned Newton, Tom’s closest friend and now the treasurer of the Swift Construction Company.

Mary Nestor, of whom Ned had spoken, was a beautiful girl whom Tom hoped to marry some day, and Ned Newton was interested in a similar manner in Mary’s friend, Helen Morton.

As Tom sat there in the darkness, trying to puzzle out where he was and how he had gotten there, his thought flashed to Mary.

“I wonder what she’ll think?” he mused. “I’d better get to a telephone and explain. Let’s see. I was coming back from town and I saw some fellow sneaking along behind the bushes. I met Ned. I went down a flight of stairs in a hole—though how they could be there and I not know it, is more than I can fathom. Then they doped me. But who did it and why, I don’t know. I’ll soon find out, though. Wonder how long I’ve been here? Feels like a week, I’m so stiff. But I’m not hurt, thank goodness!”

Tom stretched out his arms in the darkness. They responded to the action of his muscles. But when he tried to get up and walk—well, he simply could not!

“Chained fast!” cried Tom, aloud. His hands had sought his left ankle when he found that something held him fast there, and his fingers had come in contact with a chain.

For a moment he felt a sinking sensation. To be chained fast in the dark, at the bottom of some cave or dungeon, located he knew not where, was enough to take the heart out of any one. But not for long did Tom Swift give way to despair.