In O. Henry’s story “Hearts and Hands”, Miss Fairchild met by chance her old acquaintance Mr. Easton in a train compartment in the West. The moment she recognised him sitting in the opposite seat, she held out her gray-gloved hand with a lovely smile.
 
Mr. Easton roused himself sharply at the sound of her voice, felt embarrassed for a moment and greeted her with his left hand, saying —

I’ll ask you to excuse the other hand; It’s otherwise engaged just at present.

Now, Miss Fairchild discovered that his right hand was handcuffed with the left one of another man. This brought the suspicion in her mind that her friend might have been involved in some unlawful activities and hence was arrested. This is why the “glad look in the girl’s eyes slowly changed to a bewildered horror “.