Wallace does not like the way the play ends because the dog dies, and if the dog was going to die it should have just died in the beginning.
The school play is about a dog named Shep who gets hit by a motorcycle, and just as it seems that he is going to be nursed back to health, he dies.
Wallace points out that he knew the dog was going to die before he finished the book.
“Don’t be ridiculous,” the teacher snapped. “How?”
I shrugged. “Because the dog always dies. Go to the library and pick out a book with an award sticker and a dog on the cover. Trust me, the dog is doing down.” (ch 1, p. 5)
Wallace has a point—there are entirely too many books and movies where the dog dies in the end. Why must the dog die? Wallace decides that in order to make the play better, the dog should live. Soon the other kids agree with him, and want to change the ending.