It's true I bring serenity, And hang around the stars But yet I live in misery; You'll find me behind bars With thieves and villains I consort In prison I'll be found But I would never go to court, Unless there's more than one

Why this works

This riddle cleverly plays with the multiple meanings and contexts of the letter "s." The phrase "I bring serenity" suggests that the letter itself can start the word "serenity," while "hang around the stars" hints at the fact that "s" is found in the word "stars." The mention of living in misery and being found "behind bars" refers to the letter being part of the word "prison," where "s" is indeed found within it. The final clue, "Unless there's more than one," refers to the pluralization aspect, where "s" signifies more than one item, like in "thieves" and "villains." Thus, the riddle intricately weaves these meanings to lead us to the answer: the letter "s."