What should he do?

There seemed but one answer to this question. He must go back to Mr.
Preston, explain the manner in which he had lost his shirt, and ask him
for another, promising, of course, to supply the place of the one lost.
He was not sure whether Mr. Preston would accept this explanation. He
might think it was only an attempt to defraud him. But, at any rate, it
seemed the only thing to do, and it must be done at once. He entered a
passing car, for it was too late to walk.

"I wish I had taken the car down," thought Paul. "Then I shouldn't have
lost the shirt."

But it was too late for regrets now. He must do the best that remained
to him.

It was nearly ten o'clock when Paul once more stood before the door of
Mr. Preston's boarding-place. He rang the bell and asked to see him.

"You have been here before this evening?" said the servant.

"Yes."

"Then you know the room. You can walk right up."

Paul went upstairs and knocked at Mr. Preston's room. He was bidden to
come in, and did so.

Mr. Preston looked up with surprise.