“Clean forgot it!” broke in Tom. “And I can’t go now. I’ve got something to do.” Quickly he made up his mind to say nothing to Ned of what he had seen until he investigated a little on his own account. “Here, I tell you what to do,” went on Tom. “Go on, keep your date with Helen, but when you get to her house telephone to Mary for me and say I’ll be a little late. Will you?”
“Pull your chestnuts out of the fire? Is that it, Tom? I reminded you myself before supper!” laughed Ned. “Well, I don’t mind, for you’ve done the same for me. I guess Mary Nestor knows you by this time, or, if she doesn’t, she never will. But what’s the big idea?”
“Oh, I’ve just got a notion in my head,” said Tom. “I want to go to the office a moment to jot down some memoranda before I forget them. ’Phone Mary I’ll be over as soon as I can. See you later.”
“Cheek!” exclaimed Ned, and with his merry whistle he hurried off in the darkness. “I only hope Mary speaks to you when you finally get to see her,” floated back to Tom.
“Don’t you worry about Mary,” advised the young inventor. “I’ll explain to her. And tell her I’ll be along in about half an hour. I really forgot all about the engagement.”
“I’ll say you did!” playfully mocked Ned.
Then, with his chum out of the way, Tom gave himself to trying to solve the mystery. For mystery he believed it to be. Seeing a man step behind a bush and, on arriving at the bush, to find nothing of the man there was surprising, to say the least.
Sensing that it would soon be so dark that it would be useless to investigate without an illuminant of some sort, Tom made haste to gain what advantage he could from the fast-fading light. He looked sharply about without moving from his place behind the bush on the other side of which he had seen the man disappear. Then, as he could pick up here no clew to the strange happening, the young inventor moved around to the other side.
The light was a little better here and Tom saw something that made him fairly gasp with astonishment. He had moved somewhat away from the bush and almost at his feet was an opening in the ground.
“This explains it!” murmured Tom, half aloud. “A hole in the ground! He went down there. I knew he couldn’t have dug himself in as quickly as that. But that hole! I never saw it before. It isn’t any of our doing. I’d have known about it if it were.”