The Ogrum were making no attempt to attack. Craig circled the roof of the temple, seeing that sub-machine guns covered all approaches. A wind, moving from the direction of the swamp, brought with it the sound of the dinosaurs. The scene was like a setting from some fantastic movie—a full moon burning like a huge fire on the horizon, incredible beasts screaming in the night, a group of embattled humans on the roof of a temple as old as time.
"We've got them!" Craig thought. "They can't get to us and they don't dare attack. If they wait an hour—"
In some hidden spot outside the temple something went plunk. The sound was not sharp enough to be called an explosion. It was a plunk, like a rock falling in a rain barrel.
A small round object arched slowly through the air and hit on the roof of the temple. It also went plunk. No explosion. Just a plunk. A cloud of white smoke puffed out.
"What the devil is that?" Craig thought uncertainly. "Are they throwing grenades at us? Was the first grenade a dud?"
He started toward the grenade. A whiff of the smoke stung his nostrils, sent a warning bell clattering wildly in his brain.
"Gas!" he yelled. "They're throwing gas grenades at us. Stay away from that smoke."
The Ogrum had attacked the Idaho with their sleeping gas! The guards in the temple had carried sacks of what Craig had thought were ordinary grenades. They had been gas grenades!
Plunk went the projector outside the temple. Plunk went the grenade that struck on the roof.