Murder at the Grammies

All the adjectives, adverbs, verbs and other parts of speech are in attendance at the annual Grammar Award Festival.  All are vying to be chosen as the year’s Most Important Part of Speech or the Most Important Punctuation Mark.  But most are discouraged because Nathaniel Noun manages to win the top award every year.  As the winner is about to be announced, the lights go out, then on and — Nathaniel Noun has been murdered!  The superhero, Grammarman, comes to the rescue and solves the crime using a sentence diagram.