With a series of puffs and chugs a big, shiny motor cycle turned from the road into the graveled drive at the side of a white farmhouse. Two boys sat on the creaking saddles. The one at the front handle bars threw forward the clutch lever, and then turned on the power sharply to drive the last of the gases out of the twin cylinders.

The motor cycle came to a stop near a shed, and the two lads, swinging off, looked at each other for a moment.

"Some ride, that!" observed one. "You had her going then, Blake!"

"Just a little, Joe—yes. It was a nice level stretch, and I wanted to see what she could do."

"You didn't let her out to the full at that; did you?"

"I should say not!" answered the one who had ridden in front, and guided the steed of steel and gasoline. "She'll do better than ninety miles an hour on the level; but I don't want to ride on her when she's doing it."

"Nor I. Well, it was a nice little run, all right. Funny, though, that we didn't get any mail; wasn't it?"

"It sure was. I think somebody must be robbing the post-office, for we ought to have had a letter from Mr. Hadley before this," and he laughed at his own joke.

"Yes," agreed Joe, "and I ought to have had one from—"

He stopped suddenly, and a blush suffused the tan of his cheeks.

"Might as well say it as think it," broke in Blake with another laugh that showed his white, even teeth. "Hasn't Mabel written to you this week?"

"What if she hasn't?" fired back Joe.

"Oh, nothing. Only—"

"Only I suppose you are put out because you haven't had a postcard from Birdie Lee!" challenged Joe.

"Oh, well, have it your own way," and Blake, with a shrug of his broad shoulders, began to wheel the motor cycle into the shed.

"No, but it is queer; isn't it?" went on Joe. "Here we've been back from the flood district over two weeks now, and we haven't had a line from Mr. Hadley. He promised to write, too, and let us know what sort of moving pictures he might be in line for next. Our vacation will soon be over, and we don't want to be idle."

"That's right," agreed his chum. "There's no money in sitting around, when the film isn't running. Oh, well, I suppose Mr. Hadley has been so busy that he hasn't had time to make his plans.

"Besides," Blake went on, "you know there was a lot of trouble over the Mississippi flood pictures—reels of film getting lost, and all that—to say nothing of the dangers our friends ran. Birdie Lee said she'd never forget what they suffered."

"I don't blame her. Well, maybe they haven't got straightened out enough yet to feel like writing. But it sure is nice here, and I don't mind if we stay another week or so," and he looked up the pleasant valley, on one side of which was perched the farmhouse where the two moving picture boys had been spending their vacation.

"It sure is nice," agreed Blake. "And it's lots more fun since we got this motor cycle," for they had lately invested in the powerful vehicle on which they had made many trips about the surrounding country.

As Blake went to put the machine in the shed, which their farmer-landlord had allowed them to use, Joe turned to glance back along the road they had come.

The farmhouse was set up on a little hill, above the road, and a glimpse of the highway could be had for a long distance. It was the sight of something coming along this thoroughfare that attracted Joe's attention.

"What are you looking at?" asked Blake, returning after having put away the motor cycle.

"That horse and buggy. Looks to me as though that horse was feeling his oats, and that the fellow driving him didn't know any more about handling the reins than the law allows."

"That's right, Joe. If he doesn't look out he'll have an upset, or a runaway."

The vehicle in question was a light buggy; drawn by a particularly large and spirited horse. Seated in the carriage, as the boys could see from their point of vantage, were two men. Who they were could not be distinguished at that distance, but the carriage was rapidly coming nearer.

"There he goes!" suddenly cried Joe.

As his chum spoke Blake saw that one of the reins had parted, probably because the driver pulled on it too hard in trying to bring the restive steed down to a walk.

Once the spirited horse felt that he was no longer under control, save by one line, which was worse than none, he sprang forward, and at once began to gallop, pulling after him the light carriage, which swayed from side to side, threatening every moment to collapse, overturn, or at least be torn loose from the horse.

"There he goes!" yelled Joe again.

"I should say so!" agreed Blake. "There are going to be some doings soon!"

This was evident, for the horse was running away, a fact not only apparent in itself, but heralded by the looks on the faces of the two occupants of the carriage, and by their frightened cries, which the wind easily carried to the watching Joe Duncan and Blake Stewart.

On the road below them, and past the boys, swept the swaying carriage in a cloud of dust. As it was momentarily lost to sight behind a grassy knoll, Blake cried:

"The broken bridge, Joe! The broken bridge! They're headed right for it!"

"That's right!" exclaimed his chum. "How can we stop them?"

Once having recognized the danger, the next thought that came to the minds of Blake and Joe, trained for emergencies, was how to avert it. They looked at each other for a second, not to gain a delay, but to decide on the best possible plan of saving the imperiled men.

"The broken bridge," murmured Blake again. "That horse will never be able to make the turn into the temporary road, going at the speed he is!"

"No, and he's probably so frightened that he'll not try it," agreed Joe. "He'll crash right through the barrier fence, and—"

He did not finish his sentence, but Blake knew what his chum meant.

About half a mile beyond the farmhouse the road ran over a bridge that spanned a deep and rocky ravine. About a week before there had been an accident. Weakened by the passing of a heavy traction threshing engine, it had been broken, and was ruled unsafe by the county authorities.

Accordingly the bridge had been condemned and partially torn down, a new structure being planned to replace it. But this new bridge was not yet in place, though a frail, temporary span, open only to foot passengers and very light vehicles, had been thrown across the ravine.

The danger, though, was not so much in the temporary bridge, as in the fact that the temporary road, connecting with it, left the main and permanent highway at a sharp curve. Persons knowing of the broken bridge made allowances for this curve, and approached along the main road carefully, to make the turn safely into the temporary highway.

But a maddened horse could not be expected to do this. He would dash along the main road, and would not make the turn. Or, if he did, going at the speed of this one, he would most certainly overturn the carriage.

The main highway was fenced off a short distance on either side of the broken bridge, but this barrier was of so frail a nature that it could not be expected to stop a runaway.

"He'll crash right through it, run out on the end of the broken bridge and——"

Once more Joe did not finish.

"We've got to do something!" cried Blake.

"Yes, but what?" asked Joe.

"We've got to save them!" cried Blake again, as he thought of the two men in the carriage. He had had a glimpse of their faces as the vehicle, drawn by the frenzied horse, swept past him on the road below. One of the men he knew to be employed in the only livery stable of Central Falls, on the outskirts of which he and Joe were spending their holiday. The other man was a stranger. Blake had only seen that he was a young man, rather good-looking, and of a foreign cast of countenance. Blake had momentarily put him down for an Italian.

"The motor cycle!" suddenly cried Joe.

"What?" asked Blake, only half comprehending.

"We might overtake them on the motor cycle!" repeated his chum.

A look of understanding came into Blake's eyes.

"That's right!" he cried. "Why didn't I think of that before, instead of standing here mooning? I wonder if we've got time?"

"We'll make time!" cried Joe grimly. "Get her out, and we'll ride for all we're worth. It'll be a race, Blake!"

"Yes. A race to save a life! Lucky she's got plenty of gas and oil in her."

"Yes, and she hasn't had a chance to cool down. Run her out."

Blake fairly leaped toward the shed where he had wheeled the motor cycle. In another instant he and Joe were trundling it down the gravel walk to the road.

As they reached the highway they could hear, growing fainter and fainter, the "thump-thud," of the hoofs of the runaway horse.

Joe held the machine upright while Blake vaulted to the forward saddle and began to work the pedals to start the motor. The cylinders were still hot from the recent run, and at the first revolution the staccato explosions began.

"Jump up!" yelled Blake in his chum's ear—shouting above the rattle and bang of the exhaust, for the muffler was open.

Joe sprang to leather, but before he was in his seat Blake was letting in the friction clutch, and a moment later, at ever gathering speed, the shining motor cycle was speeding down the road to the rescue. Would Joe and Blake be in time?