"My Prince," he said, "I have to report that this fellow's companion escaped us. I think that it was with the connivance of one or more of the men at the gate. I have ordered them all under arrest."
Xodar handed him the thoat oil and cloth.
"With this you may discover the spy among you," he said.
I at once ordered a secret search within the city, for every Martian noble maintains a secret service of his own.
A half-hour later the officer of the guard came again to report.
This time it was to confirm our worst fears--half the guards at the gate that night had been therns disguised as red men.
"Come!" I cried. "We must lose no time. On to Hastor at once. Should the therns attempt to check us at the southern verge of the ice cap it may result in the wrecking of all our plans and the total destruction of the expedition."
Ten minutes later we were speeding through the night toward Hastor, prepared to strike the first blow for the preservation of Dejah Thoris.