In O'Henry's "Heart and Hands," the conflict seems to be between Easton and Miss Fairchild. Miss Fairchild recognizes Easton while on the train; however, Easton is handcuffed to another man at the moment, and he does not want to draw her attention to it. When Miss Fairchild becomes insistent that Easton acknowledge her, the other man quickly jumps in to state that Easton is the marshal who is bringing him in to do 7 years of prison for counterfeiting.
The twist comes at the end when we learn that the unnamed man is, in fact, the TRUE marshal, and that Easton is the one heading to prison. The marshal does not want to humiliate Easton in front of an old friend by showing Miss Fairchild that Easton is the true convict.
A second twist comes at the very end when passengers who overheard the conversation recognize that a marshal would never handcuff a man to his right hand. This detail from O'Henry shows us how we often ignore seemingly obvious details when the information is not appealing to us -- two complete strangers picked up on Easton's character much quicker than an old friend.