“Bab,” she whispered, clutching at Barbara’s bathrobe until that young woman nearly tumbled backwards down the steps, “there is a light in Uncle’s study!  I suppose it is Harriet who is down there.”

It flashed across Bab’s mind to wonder, oddly, if Harriet’s visit to her father’s study at night could have anything to do with her debt to her dressmaker of five hundred dollars!  For Mollie had reported to her sister that Harriet was feeling desperate over her unpleasant situation.

“If it is Harriet downstairs I don’t think we ought to go down,” Bab objected.  “We would frighten her if we walked in on her so unexpectedly.”

“Harriet ought not to be alone downstairs,” Ruth insisted.  “Uncle would not like it.  I am going to peep in on her, and then make her come on upstairs to bed.”

Ruth led the way, with Bab at her heels.  But it occurred to Barbara that the midnight visitor to Mr. Hamlin’s study might be some one other than his daughter.  Bab did not know whether Mr. Hamlin kept any money in his strong box in the study.  She and Ruth were both unarmed, and might be approaching an unknown danger.  Quick as a flash Bab arranged a little scheme of defense.

There were two old-fashioned square stools placed on opposite sides of the hall.  Without a word to Ruth, who was intent on her errand, Bab drew out these two stools and placed them side by side in the immediate centre of the hall.  Any one who tried to escape from the study would stumble over these stools and at once alarm the household.  Of course, if Bab and Ruth found Harriet in her father’s study Bab could warn them of her trap.

“What shall we do, Bab?” Ruth asked when Barbara joined her.  “The light is still shining in the study.  But I do not want to knock on the door; it would frighten Harriet.  And it would terrify her even more if we walked right into the study out of this darkness.  But we can’t wait out here all night.  I am catching cold.”

Barbara did not reply.  They were in a difficult situation.  Suppose Harriet were in the study?  They did not wish to frighten her.  In case the veiled figure was not Harriet any speech of theirs would give their presence away.

“I think we had better open the door quickly and rush in,” Ruth now decided.  “Then Harriet can see at once who we are.”

Without waiting for further consultation with Bab, Ruth flung wide the study door.

In the same instant the light in the room went out like a flash.

“Harriet, is that you?” Ruth faltered.  There was no answer, save some one’s quick breathing.  Ruth and Bab could both perceive that an absolutely white figure was crouched in a corner of the room in the dark.

Bab moved cautiously toward the spot where she knew an electric light swung just above Mr. Hamlin’s desk.  But it was so dark that she had to move her hand gropingly above her head, for a moment, in order to locate the light.