As Max tells us, what he really likes about the Fourth of July is that it's so incredibly edgy. People feel that they can just have a blast without thinking too hard about the consequences. And yet, despite this, Max has never been to a Fourth of July fireworks display without his grandparents before, which is strange, as the display takes place right down by the millpond where he's been allowed to play for years.
But this years's going to be different. This year, Max will be heading off to the fireworks without adult supervision for the first time ever. Why? Because this time, he actually has a real-life friend to go with: Kevin, Freak the Mighty himself. As Max and Kevin spend much of their time hanging out with each other, it's only natural that they should want to go to the fireworks together. They're hoping that it'll be a fun experience.
Grim and Gram understand how close a friend Kevin has become to Max, so they let Max go to the fireworks without any adult supervision. That said, they're not super enthusiastic about it. For one thing, Gram is worried that Kevin might get crushed by someone. She seems to think that someone might actually step on him. And although that doesn't happen, thank goodness, Max and Kevin still get more than they bargain for when they're confronted by a gang of cretinous thugs led by the revolting Tony D.