Apollo urged Belmont to follow, and then they disappeared beyond the vines, which fell down and hid the opening again.
“It’s a cave, Merry!” whispered Rattleton.
“Yes,” nodded Frank; “it may be one of the many entrances to the great cavern of the ‘queer’ makers. This may lead into the cave occupied by Carter Morris!”
“Then let’s get in there quick!” exclaimed Harry, eagerly. “If we don’t, we may lose track of those men.”
“We must use something like caution, my boy. If we were to rush in after them, it might do us up, for they may be laying for us.”
So the mouth of the cave was approached with caution.
When they had reached it, Frank listened.
From a distance inside he could hear voices, and, peering through the vines, he caught the glimmer of a light.
“Come in quickly after me, Harry,” he directed. “Be ready to fight for your life if attacked.”
Rattleton’s heart was in his throat, and he felt that they were plunging into unknown and terrible danger, but he said: