After you read the short story, you might want your students to read this script. Students love reading scripts as it is very student-centered and gets them involved. I think they retain more when they are part of this kind of a reading.
This script is arranged into eight parts, four characters and four narrators, so if you have, let's say, a class of 24, you could have three groups reading it aloud simultaneously, two in the class and one in the hallway. The script itself will take less than a full period, so you can use one of the following activities, such as the study questions or the vocabulary activity that I put together, and have it go over into two days.
"Charles" is a great story for exploring the concept of "ownership" vs. "projection" or having blind spots and seeing flaws elsewhere, rather than 'fessing up oneself. I like putting together scripts from short stories. If you like this, see my store for other scripts.