They were not on duty themselves, but they knew that all the South Carolina earthworks and batteries were manned.

What would happen?
It still seemed almost incredible to Harry that the people of the Union--at least of the Union that was--should fire upon one another, and his pulse beat hard and strong, while he waited with his comrade.
As they stood there gazing out to sea, looking for the black speck that should mark the first smoke of the Star of the West, Harry became conscious that another man was standing almost at his elbow.

He glanced up and saw Shepard, who nodded to him.
"I did not know that I was standing by you until I had been here some time," said Shepard, as if he sought to indicate that he had not been seeking Harry and his comrade.
"I thought you had left Charleston," said Harry, who had not seen him for a week.
"Not at such a time," said Shepard, quietly.

"So much of overwhelming interest is happening here that nobody who is alive can go away." He put a pair of powerful glasses to his eyes and scanned the sea's rim.
He looked a long time, and then his face showed excitement.
"It comes! It comes!" he exclaimed, more to himself than to Harry and Arthur.
"Is it the steamer?
Is it the Star of the West ?" exclaimed Harry forgetting all doubts of Shepard in the thrill of the moment.
"Yes, the Star of the West! It can be no other!" replied Shepard.
"It can be no other! Take the glasses and see for yourself!" When Harry looked he saw, where sea and sky joined, a black dot that gradually lengthened out into a small plume.

It was not possible to recognize any ship at that distance, but he felt instinctively that it was the Star of the West.