In a few moments they were down the dark passageway and at the door. It was wide open.
“Now, how do you suppose that happened?” queried Bess. “Mrs. Cupp is so particular about keeping it locked.”
“The boy opened it when he came through,” said Nan.
“From the inside?” gasped Bess. “Do you think he’s been hiding in one of the trunks?”
Nan showed her quickly that the knob of the spring lock was on the inside of the trunk-room door. One could easily get out of the room without a key.
“But for goodness’ sake!” cried Bess. “Tell me how he got in here?”
“That’s what I am going to show you,” said her chum, laughing. As they walked down the long room, Nan snapping on a light here and there to show the way, she told her chum about the movable part of the partition and how she had made the discovery.
Bess’ interest and curiosity was roused to the highest point.
“What did I tell you, Nan Sherwood?” Bess cried. “There is an underground passage down to the boathouse!”
“We’ll just see,” agreed Nan.