It was not till they were entering the grim old door of the grim old house that they thought again of Billie's new discovery—the trunk that jingled.
"Goodness! how could we ever have forgotten it?" cried Billie as she, with Violet and Laura, fairly flew up the stairs, leaving the bewildered boys to follow them.
"Now what's up?" asked Teddy, as he came into the room where the girls had left their treasure. "So many things are happening all at once that it's enough to make a fellow's brain reel."
"It all depends on the brain," said Billie, looking up at him with a twinkle in her eye. And all Teddy did was to look sad and reproachful.
"Say, what shall I be doin' with this?" asked Mrs. Gilligan, and they turned to see her great bulk looming in the doorway. In her hand she held the rat trap with the dangling rat.
"Gee, where did you get it?" cried Chet, jumping to his feet from where he had been kneeling with Billie, examining the shabby trunk.
Mrs. Gilligan paused a moment and a gleam of humor shot into her eyes.
"You've been askin' to see ghosts, Mr. Chet," she said, with a chuckle, "and you sure have got your wish this day. That airman was the first. Here is the second one!"