Here's how it unfolds:
* Greg, feeling dejected after a disastrous attempt at a "cool" makeover, arrives at the dance and immediately feels out of place. He sees Rowley dancing with a girl he likes, and tries to avoid further humiliation.
* He encounters a group of bullies, led by the menacing Rodrick, who are picking on Rowley. Greg is initially hesitant to intervene, but his conscience and loyalty to his friend win out.
* He steps in and defends Rowley, even though it means standing up to the much bigger Rodrick. The fight isn't glamorous, but it shows Greg's courage and earns him respect.
* The climax is not a typical physical fight, but a more nuanced confrontation where Greg's bravery and commitment to his friend defy the social pressures and norms of the school environment.
This moment marks a significant turning point for Greg. He realizes that being "wimpy" doesn't mean being weak, and that true strength lies in being true to himself and standing up for what he believes in.