"Say, what are you doing up there?" a girl's voice hailed them from the bottom of the steps, and Chet thought he recognized it as Billie's. "Are you walking in your sleep or have you gone crazy? Come down here quick, we need you."
"Keep still," Chet yelled back. "We're looking for your aeroplane ghost.
Can't you hear it?"
"Yes. But, oh, Chet," Billie's voice was tremulous, "the piano is playing itself again. Won't you come down? We're afraid to stay here all alone."
"Great Scott! all the spirits are roaming at once," cried Teddy, straining his eyes to see through the darkness as the humming of the motor came nearer.
"There, isn't that it?" cried Ferd, pointing eagerly through the trees toward a little patch of sky, palely illumined with stars.
"I think I saw it," said Chet, rubbing his eyes impatiently. "It's so confoundedly dark—"
"Oh, won't you please come down?" wailed Billie's voice from the spooky depths of the attic. "I'll die of fright if I have to stay here another minute."
This appeal moved the boys, and they began reluctantly to descend the ladder, keeping their eyes all the time on the pale patch of sky.
"Where are the others?" asked Teddy, as he reached Billie's side.
"They're down looking for the ghost," answered Billie, as she ran down the stairs in front of them. "They sent me to get you boys, and I found you gone. Mrs. Gilligan," she added, with a hysterical giggle, "has the broom and Laura has the poker."