Betty Lou sees a mess in front of her friend's yard, and wonders what happened. Sherlock Hemlock arrives and offers to help solve the mystery. He comes to the conclusion that Twiddlebugs caused the mess after being chased by a monster. However, Betty Lou figures out that somebody had a birthday party, and Roosevelt Franklin proves her right. But there's a surprise ending, showing you should never underestimate a professional detective like Sherlock.