"One thing is plain;" she said, "there’s a girl about who looks like me; but goodness knows who she is, or where she comes from. Look here, Hughie, will you keep your eyes open--now you know. I’ll try and follow it up too, and I promise I’ll tell you what I find out even if I don’t tell other people." "I see. Yes, all right, Pam," agreed the Midget with dignity. As a matter of fact he was really not quite sure whether he did see. It was all rather startling; why should there be a girl exactly like Pam--and with the same pigtail even? However, there it was. He had said he would believe what his sister told him. "Well, good-night, Hughie; we shall see what happens next," said Pamela. She was not laughing at all, her face wore the same keen look. "And remember you promised not to say one word to a living soul, whatever happens." "All right. I promise. Good-night, Pam," and Hugh raised his face to be kissed rather meekly. He felt as though all this was rather serious. Pamela went away to her own room and sat down in the low window-seat to puzzle out the position. There was a girl in Bell Bay so like herself that two people who knew her well had been completely deceived, yet nobody had arrived in the cove--publicly. Indeed, there was no place for them to arrive at, without the inhabitants being aware. "The queer part is," thought Pamela, "that nobody is worrying with curiosity, because whenever anyone sees her they think it’s I, and naturally they don’t notice any more. Whatever that girl does will be put on my shoulders, and I can’t go and say she’s there because I don’t know." She looked at the silver, clear, clean moon, riding so gaily up and up, and at the inky shadows of rocks away down on the white shining sand of the cove. Everything was painted black and white, and the ripple of the sea was a laughing whisper. Pamela was used to this fairy scene in all sorts of phases, but to-night--probably because of the Mystery Girl--she felt as though something uncanny were abroad, and to shake herself free from the feeling she opened her precious handbook, and proceeded to search through it from end to end. "What should a person do--what would a Patrol Captain, or any experienced Guide do, if she found she had a ’double’? Practical information about making jam tins into candlesticks, or how to meet a mad dog! Splendid directions for camping and tracking--_tracking_!" Pamela paused and thought about that. She studied the means for finding out a bicycle-track, what sort of bicycle--which way going. That might be useful if the girl rode a bicycle. Footprints might be followed up if she could be sure what sort of shoe the girl wore. She shut up the book, and began to undress, gazing dreamily out at the moonshine all the time, utterly unconscious what that moonshine was to show her one night--in the near future.