Middle-schooler Greg Heffley nimbly sidesteps his father's attempts to change Greg's wimpy ways until his father threatens to send him to military school.

"After a disastrous field day competition at school, Greg decides that when it comes to his athletic career, he's officially retired. But after his mom urges him to give sports one more chance, he reluctantly agrees to sign up for basketball. Tryouts are a mess, and Greg is sure he won't make the cut. But he unexpectedly lands a spot on the worst team. As Greg and his new teammates start the season, their chances of winning even a single game look...