"Looks like rain."
"It sure does," agreed Joe, looking up.
As though in corroboration, there was an ominous rumble of thunder. The wind had died down. Every leaf, every blade of grass was still. The clouds were massing silently.
However, the storm held off, and although the sky was overcast and threatening, twilight fell without rain. Frank and Joe, from their hiding place in the bushes, watched the four men moving aimlessly about the cave that afternoon. Two of them had remained inside the cave for a long time while the other pair chatted on the rocks outside.
Night came at last. From the interior of the cave came the flicker of flames, and the Hardy boys knew that the gang was making a fire for the night.
The heat was still oppressive. Darkness fell without moon or stars.
"We'll soon be able to creep up on them now," said Frank. "If we can only get close enough to hear what they're saying we'll probably be able to make sure if they have Chet and Biff with them."
The boys waited until the fire had died down. The four men had all disappeared within the cave.
"Quiet, now," Frank whispered. He began to make his way out of the undergrowth. Joe followed close behind. They crept up toward the entrance to the cave.
They were about half-way across the open space when the whole scene about them was suddenly revealed with startling clarity in the livid glow of a flash of lightning. This was followed immediately by a crash of thunder that seemed to shake the very rocks on which they stood. As though this were but a prelude, rain began to fall, gently at first, then with increasing force. Other lightning flashes followed. Then the storm broke in all its fury.