re walking rapidly towards the heights of
Caesar's Camp, the southern boundary of the defences of Ladysmith, and a
position of the most vital importance to the garrison, for with the
Boers in possession of it their guns would have forced our troops to
surrender.

"There's some treachery going on!" Jack whispered as they walked along
side by side. Then he explained what he had seen, and told them how
Piet Maartens, and two men dressed presumably as colonial volunteers,
were marching towards Caesar's Camp.

"There is certainly something wrong," Mr Hunter replied hurriedly.
"Now what had we better do! Ah, I know! You two follow them, and I
will go to the quarters of the officer in command of the pickets
to-night and warn him. What can those spies want! Keep your eyes open,
lads. It looks as though our friends were about to make an attempt to
take Ladysmith."

A moment later Mr Hunter was gone, and Jack and Guy hurried on till
they were within sight of the men they were following. It was now
almost dark, and having ascertained the direction in which they were
marching, the two took to their heels, and, making a wide detour, ran up
to the trenches at the top of the hill.

"Wait here, Guy, while I go over and speak to the officer on duty," said
Jack. "I'll be back directly."

Slipping across the turf, he was soon challenged by a sentry and brought
to a sudden stop with the man's bayonet at his chest. Then he was taken
to the officer.

"I've some important news to give you," he said. "Can I see you alone!"

"Certainly! Come in here," was the answer; and Jack was led into a
trench.

"There's something going on to-night," Jack whispered. "A Boer I knew
in Johannesburg is marching up here with two men, all dressed as
volunteers. They are all spies, I believe, and I have come to warn
you!"

"Spies! By Jove, we'll get hold of them immediately they appear!"
exclaimed the officer.

"Don't you think it would be well to let them do whatever they are
coming for," said Jack thoughtfully. "You might set a watch on them,
and as soon as you have found out their game arrest them. I should warn
your sergeants and a few of the older men, so as to be ready. Mr
Hunter thinks it looks as though the Boers were about to make a rush."

"By George, they'd better not!" the officer exclaimed. "But I'll do as
you suggest, and what is more, I'll send a man over to warn the fellows
on Wagon Hill."

"Very well! I'll sli