Dead End in Norvelt closes when Jack finally gets the promised ride in the J-3 airplane with his father. So, while Jack has learned some valuable lessons over the summer, he seems to hit a dead end by making yet another dumb decision: he and his father fly over the Viking movie theater and fulfill their plan to lob water balloons at the giant movie screen.
And not just water balloons—water balloons filled with red paint. Holy parental-approved vandalism, Batman! Jack's father defends this happy little foray into property destruction by saying, "Red should leave a little more history" since "[w]ater will evaporate" (28.91). So, they proceed to rain down crimson-filled bags onto the giant screen (which is currently showing Sink the Bismarck, yet another war movie).
His father's attitude toward this is: "All is fair in love and war" (28.91), but Jack feels uneasy about it. He sees that the "red blotches had exploded against the black-and-white movie images and the red paint ran like bloody tears down the face of the screen" (28.100). And he doesn't like this one bit—and no wonder, because it all seems a little too much like the bloody streaks that his nose leaves everywhere.
As panicked moviegoers begin to flee the theater, Jack is reminded of the event that kicked off the summer for him: shooting the Japanese rifle. We can almost see the light bulb going off in Jack's head: "The reason you remind yourself of the stupid stuff you've done in the past is so you don't do it again" (28.102).
This mature realization gives him the strength to realize his Dad is being a jerk, and Jack tells him that the so-called joke is not funny. Despite this, Jack also recognizes that "being stupid at that moment would forever be a part of who I was" (28.107). In other words? He's done this, and he's always going to have done it. He'll never be a guy who didn't think it would be fun to throw red-paint-filled water balloons at an outdoor movie screen.
Why, you might ask, would Jack admit to being stupid so close to the end of the story? Has he not learned anything? The answer to that can be found in the final obituary, a fitting close to Jack's summer experiences:
"On the morning of August 17, Jack Gantos was released from being grounded by his parents. But stay tuned because on August 18 he might be grounded all over again—unless he remembers his history!"
In other words, he's learned that he is allowed to make mistakes, and that he will make mistakes. Everyone does. But no one can continue to do idiotic things over and over and get away with it. That's not what growing up is all about. In the end, Jack really has learned Miss Volker's lesson regarding history, and it has nothing to do knowing on what date the bombing of Hiroshima took place—it has to do with being able to learn from your mistakes.