"Erica's bike. She's left it by the roadside and gone forward on foot. There's her front lamp on it, unlit--but perhaps she had no matches," a surmise they afterwards found out to be fact. "We'd better leave ours here too. They're more nuisance than use now we can't ride them. We can take the front lamps with us." So they propped their bicycles by the side of the road, which was now little more than a track. The dense mist had settled down thicker than ever, so that they could hardly make out the ground at their feet, and the lamps only seemed to light up and reveal a few yards of greyish vapour. It all felt very weird and mysterious. To go on now had become a matter of real danger. But Erica was somewhere ahead, in the darkness, alone, and to go back was impossible. The two girls shouted and halloed at the top of their voices, but the mist only returned the echoes of their own cries. "Coming on?" asked Duane curtly. "Of course," returned Kitty as briefly. "We must keep to the track though. Won't do to get lost ourselves." They stumbled forward again, neither of them daring to voice their secret fear that Erica, frightened and lonely and without a light, had wandered off the track when the mist and the darkness had descended so quickly, and was lost on the downs. Such a possibility made them both shiver. They stopped at brief intervals and shouted, Kitty raising piercing calls of "Coo-ee!" and then listening intently, but with no result. It would be hard to say how far they had gone--their only guide was the track, which they dared not leave and which they followed mainly by the feel of it beneath their feet--when at last Kitty's sharp ears caught a faint, answering call. They advanced, shouting again, and again came the faint answer from the darkness. Kitty halted. "It's from our left somewhere, not ahead. Come on." They turned to their left and by the light of their lamps advanced cautiously over the down turf, guided by the voice. Before long, a dark mass loomed up with startling suddenness in the pale rays of their lamps. It was a shepherd's hut, and inside, crouched in a forlorn heap upon the hard, bare floor, they found the runaway. [Illustration: "Crouched in a forlorn heap upon the floor, they found the runaway."] "Oh, I'm so glad you've come. I'm so c-cold and t-tired." "However did you find this place?" asked Kitty, peering around. "You see, the road got so rough," Erica replied in a tired voice. "I left my bike and walked, and then I knew I must have taken the wrong road; but I was so tired, I didn't want to go all the way back. I thought perhaps it would lead to some houses or a village if I kept on. But it got so dark and I was frightened. I couldn't see my way and then I was wandering about and I ran right into this hut. Oh, I wish I was home. I heard you calling at last, but there's a big blister on my heel, and I--I c-can't walk any more."