It was a man, and he was running in short hops, as if he were using a stick or cane to assist him in covering ground rapidly.
Behind the fleeing man Tom and Hippy discovered a second figure.

It was Willy Horse.

The first figure, as the two Overlanders started for him at a run, had dashed out over the broken and bent spiles of the dam, hopping from one spile to another with remarkable agility, with Willy Horse in close pursuit.
The hopping man, reaching the end of the spiles at the middle of the dam, halted, hesitated, and the Indian was upon him.
"It's Peg Tatem!" cried Hippy.

"He's the scoundrel who did this thing." A knife in Peg's hand flashed in the moonlight, another appearing in the hand of the Indian, and out there on their precarious footing the men stood, thrusting and parrying, with their two-edged blades, watched with breathless interest by the entire Overland party, who had rushed to the river's edge.
A sudden uproar was heard in the direction of the bunk-house.

The lumberjacks having discovered that a fight was in progress were running towards the river to see if they too could not get into the fray, for a lumberjack loves nothing in the world so violently as he loves a fight.
"Keep out of it!" ordered Tom as he saw that the jacks were headed for the path that Peg and Willy had taken.
"Tom! Do something!" begged Grace.