"The person who locked the door assuredly did not make his exit by the window," Kelson remarked with a laugh, as he looked up at the sheer surface of the upper wall; "unless he was bent on suicide, in which case we should have found what was left of him at the foot of the tower."
As they went on round the house, Miss Morriston was seen coming up the drive. Her brother hurried forward to meet her.
"I say, Edith," he exclaimed, "we are in a great fix. Can you explain how the door of the top room in the tower comes to be locked with the key inside?"
Miss Morriston looked surprised. "What, Dick?"
"We can't get in," Morriston explained. "We found the door locked and the key missing, and then when Alfred tried another key, he found the right one was in the lock but inside the room."
Miss Morriston thought a moment. "My dear Dick, the door can't be locked."
"It is, I tell you," he returned; "most certainly locked. We have tried it and found it quite fast."
"Then there must be someone in the room," his sister said.
"That," Morriston replied, "seems the only possible explanation. But I shouted several times and got no answer."
"Someone playing you a trick," and the girl laughed.