Since I haven't read the 'bad day on the midway novel', it's difficult to say precisely. However, generally speaking, a novel with such a title might focus on the seedy or difficult aspects of a midway. It could be about the underbelly of the carnival life, such as the exploitation of workers, the disappointment of visitors who realize the midway isn't as glamorous as they thought, or the dark secrets that lurk within the seemingly fun and festive environment. There could be a story of a character who discovers something unpleasant about the midway and has their day ruined as a result.
Well, without having read the 'bad day on the midway novel', I can only guess. It could be centered around a character who has a really tough day at a midway. This could involve things like financial troubles if they are running a booth, or personal dramas that unfold while surrounded by the chaos and excitement of the midway environment. Maybe there's a conflict between different groups of people at the midway, like the carnival workers and the local residents. The midway is often a place full of energy and different types of people, so there are many possibilities for a 'bad day' story.