"I say!" called Jack to his companions, who were now some distance ahead of him. "I've got to run back and mail a letter. Go on and I'll catch up to you."
"All right," said John. "We'll walk slow."
Intent on rectifying his forgetfulness, Jack turned back on the run. He did not see three figures sneaking into the shadow of a dark doorway just as he turned.
"We'll have him just where we want him," whispered one of the youths who had been following the students.
"You're not going to be three to one, are you?" asked one of the trio.
"No, I guess Jerry Chowden is a match for Jack Ranger any day," was the answer. "You two can look on, and see me wallop him."
Jack made good time back to the post-office, and came hurrying along the street, whistling a lively tune. In the meantime the three plotters had walked ahead, taking care not to get too near Nat and John. The latter, however, had walked faster than they intended, so that they were a good quarter of a mile ahead of Jack.
As the latter came opposite the last building that stood on the edge of where there were a number of vacant lots, he was surprised to hear a hail.
"Hold on there!" someone cried.
"Who are you?" asked Jack, looking around. Then, as three figures emerged from the shadows and blocked his path, he exclaimed: