It was believed that this man had remained there with Rhodes and Carter for a period somewhat extended. But who had this mysterious visitor been? It was, of course, held as certain that something told by this man to the scientist and his companion was the key to the mystery. But what had the visitor told them? We knew that Rhodes and Carter had gone to Mount Rainier. But why had they so suddenly abandoned all their plans and gone to the mountain? On the mountain they had disappeared. More than that no man could tell. And now we come to another enigma. Rhodes seldom drove a car himself. On this trip, however, he was at the wheel. The only other occupant of that car was Carter. And Rhodes had left with his chauffeur, Everett Castleman, instructions over which I puzzled my head a good deal but without my ever becoming any the wiser. These instructions were somewhat extraordinary. They were these: If Rhodes had not returned, or if no word had been received from him, within a period of ten days, then Castleman was to go to Mount Rainier. He was to go to Paradise, and he was to go on the eleventh day. And he was to maintain a strict silence about everything appertaining to this whole proceeding. At Paradise he was to remain for another period. This was one of eight days. If, at the expiration of that time, neither Rhodes nor Carter had appeared, Castleman was, on the ninth day, to take the car back to Seattle, and then the imposition of silence regarding that part which Castleman had played was at an end. _The_ mystery, of course, was what had become of Milton Rhodes and William Carter. Had some fatal accident occurred? Had they, for instance, fallen into a crevasse and perished? Or had they just gone off on some wild mountain hike and would they be returning any day? As to this last hypothesis, those instructions given to Castleman should have shown its utter untenability. And so the time passed. And Milton Rhodes and William Carter never came back. Week followed week. Month followed month. All hope was abandoned--had been abandoned long before the _Multnomah_ entered Elliott Bay. And that mysterious visitor? Why had he not spoken? Why had he not come forward and told what he knew? Where was he? Had he too vanished? Had he joined Rhodes and Carter on the mountain, and had the three vanished together? And what had he told them there in Rhodes' library on that fateful day? Thus matters stood when one afternoon an automobile came gliding into my place, and there in it were Milton Rhodes and William Carter! With respect to the mystery of their disappearance, I could for some time elicit from them no enlightenment whatever. Instead: "Where is she, Darwin?" asked Milton Rhodes, looking about. "Let me see her! Let me meet her! Quick!" "So you know about my Sleeping Beauty in the Ice?"