De Spain, naturally reckless, had won in Nan a girl hardly more concerned. Self-reliant, both of them, and instinctively vigilant, they spent so much time together that Scott and Lefever, who, before a fortnight had passed after Duke's return home, surmised that de Spain must be carrying on some sort of a clandestine affair hinting toward the Gap, only questioned how long it would be before something happened, and only hoped it would not be, in their own word, unpleasant. It was not theirs in any case to admonish de Spain, nor to dog the movements of so capable a friend even when his safety was concerned, so long as he preferred to keep his own counsel--there are limits within which no man welcomes uninvited assistance. And de Spain, in his long and frequent rides, his protracted absences, indifference to the details of business and careless humor, had evidently passed within these limits. What was stage traffic to him compared to the sunshine on Nan's hair; what attraction had schedules to offer against a moment of her eyes; what pleasing connection could there be between bad-order wheels and her low laugh? The two felt they must meet to discuss their constant perplexities and the problems of their difficult situation; but when they reached their trysting-places, there was more of gayety than gravity, more of nonchalance than concern, more of looking into each other's hearts than looking into the troublesome future. And there was hardly an inviting spot within miles of Music Mountain that one or the other of the two had not waited near. There were, of course, disappointments, but there were only a few failures in their arrangements. The difficulties of these fell chiefly on Nan. How she overcame them was a source of surprise to de Spain, who marvelled at her innocent resource in escaping the demands at home and making her way, despite an array of obstacles, to his distant impatience. Midway between Music Mountain and Sleepy Cat a low-lying wall of lava rock, in part sand-covered and in part exposed, parallels and sometimes crosses the principal trail. This undulating ridge was a favorite with de Spain and Nan, because they could ride in and out of hiding-places without more than just leaving the trail itself. To the west of this ridge, and commanding it, rose rather more than a mile away the cone called Black Cap. "Suppose," said Nan one afternoon, looking from de Spain's side toward the mountains, "some one should be spying on us from Black Cap?" She pointed to the solitary rock. "If any one has been, Nan, with a good glass he must have seen exchanges of confidence over here that would make him gnash his teeth. I know if I ever saw anything like it I'd go hang. But the country around there is too rough for a horse. Nobody even hides around Black Cap, except some tramp hold-up man that's crowded in his get-away. Bob Scott says there are dozens of mountain-lions over there."