When Mr. Wilson's Aunt Emma pays him a visit, she takes an instant liking to Dennis, causing Mr. Wilson to fear that she will make Dennis her heir instead of him.
Dennis takes Mr. Wilson's lawn edger without asking, so when Mr. Wilson sees Mrs. Elkins using an edger she recently purchased, he takes it believing it was stolen from him.
When Mr. Wilson's money is lost at Quigley's market through a hole in his pocket, he cannot pay Dennis for washing his car - but Dennis misinterprets "the market" to mean stock and assumes Mr. Wils...
Henry gets a ticket for walking on the grass in the park. When Mr. Wilson hears about it, he thinks it isn't fair, so he convinces Henry to go to court and contest it.
Mr. Wilson sees large footprints in his yard caused by Dennis' new novelty shoes and thinks they may be from a monster that has been reported in the newspaper.