"Never go away an' leave a fire lit," Hopalong replied, sententiously, closing the banging door and fastening it shut. A streak of lightning quivered between earth and clouds and the thunder rolled in many reverberations along the cliffs of the valley's edge, to die out on the flat void to the west. Down the wind came the haunting wail of a coyote, sounding so close at hand that Red instinctively reached for his rifle and looked around.

"Take mine!" jeered Hopalong, mounting, having in mind the greater range of his weapon. "You'll shore need it if you want to get that feller. Gee, but it's dark!"

It was dark and the air was so charged with electricity that blue points of flame quivered on the ears of their horses.

"We're going to get h—l!" shouted Red above the roar of the storm. "Every time I spits I make a streak in th' air—an' ain't it hot!"

One minute it was dark; another, the lightning showed things in a ghastly light, crackling and booming like a huge fireworks exhibition. The two men could feel the hearts of their horses pounding against their sides, and the animals, nervous as cats, kept their ears moving back and forth, the blue sparks ghostly in the darkness.

"Come on, get out of this," shouted Hopalong. "D—n it, there goes my hat!" and he shot after it.

For reply Red spurred forward and they rode down the steep hill at a canter, which soon changed to a gallop, then to a dead run. Suddenly there came a roar that shook them and the storm broke in earnest, the rain pouring down in slanting sheets, drenching them to the skin in a minute, for their slickers were no protection against that deluge. Hopalong stripped his off, to see it torn from his grasp and disappear in the darkness like a frightened thing.

"Go, then!" he snapped. "I was roasting in you, anyhow! I won't have no clothes left by th' time I hits th' Bend—which is all th' better for swimming."

Red slackened pace, rode at his friend's side, their stirrups almost touching, for it was safer to canter than to gallop when they could not see ahead of them. The darkness gradually lessened and when they got close to the dam they could see as well as they could on any dull day, except for a distance—the sheets of water forbade that.

"What's that?" Hopalong suddenly demanded, drawing rein and listening. A dull roar came from the dam and he instinctively felt that something was radically wrong.