Dennis accidentally ties an important note that belongs to Mr. Wilson on a pigeon, so Mr. Wilson, Henry, Tommy and Dennis go to where the pigeons roost at night at a spooky house to try and get the note back and end up in the middle of a collage fraternity initiation meant for new fraternity members. After a bunch of twists and turns they find the pigeon with the note tied on it.
Mr. Wilson has written a book on his Uncle Ned's life for his publisher. Uncle Ned however does not want the book to be published So Mr. Wilson goes up to Uncle Ned's house to try and reason with him. The only thing is that Uncle ned has gone down to Mr. Wilson's house to talk with him as well. Now it is up to Dennis to try and keep Uncle Ned from meeting the publisher until Mr. Wilson can return home again.
Dennis gets a new Principal, Mr. Spivey who is very strict at his school. Mr. Spivey and Dennis get off on the wrong foot at first However, Johnny Brady takes note of that and because he wants to be on the pitcher on the school baseball team. So, he sets Dennis up by drawling a picture on the back of his paper making fun Mr. Spivey's height. When Mr. Spivey finds it he naturally assumes Dennis is the one that drew it so he punishes Dennis by kicking him off the baseball team and keeping him after school. As the news travels Mr. Wilson, Mr. Quigley and Mr. Finch all go to the school a few minutes apart and talk to Mr. Spivey each claiming to be Henry Mitchell to stand up for Dennis. Mr. Spivey gets confused but soon realizes he misjudged Dennis and ends up apologizing and putting Dennis back on the school baseball team.