l under the mountain,
there was a sharp crack.

"Look out!" yelled Bud, as a bullet "zinged" viciously over their heads.

In an instant Old Billee had whipped out his gun and sent a shot toward
a group of horsemen along the river bank.

"There they are! Del Pinzo and his gang!" yelled Dick, as another
bullet sang over his head. "Come on! Let's get 'em!"

"No use!" drawled Snake. "They've got hosses--we ain't!"

And a moment later the gang of conspirators, firing another harmless
shot, swept out of view.

A group of men swarmed from the store and adjacent shacks, roused by
the early-morning shooting, and with amazement they greeted our friends
and heard the strange story.

"What day is it?" asked Bud.

"Friday," some one answered.

The mystery-solvers looked at one another in amazement.

They had been in the tunnel nearly forty-eight hours without sleep, nor
did they feel the need of it, so exciting were the events that
transpired.

But late, or, rather, early as it was, they managed to get in the store
to use the telephone. And when the gray dawn was breaking across Pocut
River, Bud learned, over the wire, from one of his father's cowboys
left at Flume Valley, that the reservoir was again being filled.

"Hurray! It's all right!" yelled Bud, almost as loudly as the Kid
would have done. "I guess, from now on, we'll have no trouble. But
I'm going to see if we can't get Del Pinzo. He and his gang certainly
tried to blow up the place, and us with it."

"To say nothing of trying, as I believe, to drown, us like rats in
there, by shutting off and turning on those queer streams," added Nort.

"Do you think they really meant to drown us or blow us up?" asked Dick.

That question was never answered, for Del Pinzo and his more intimate
associates disappeared after their flight from the tunnel, when they
fled following the shifting of the lever and the lighting of the fuse.

There was dynamite tamped in among the rocks, and but for the stamping
out of the fuse the tunnel never would have carried any more water to
Flume Valley, and those in it might never have come out.

Hank Fisher stoutly denied that Del Pinzo was acting for him either in
planting the explosives or in shutting off the water from the reservoir
of the boy ranchers. But everyone had their suspicions.

For that it was Del Pinzo who had sent, or caused to be sent the
mysterious warnings, no one doubted. Nor did anyone doubt but that the