Released November 2015, this movie involves the Mingo Kids forcibly splitting up, a lot of good changes, Patty getting expelled and a daring heist involving guns.
Greg, now heading straight for high school, is running out of time to fix his middle school failures. He realizes that if high school won't be a mess like middle school was, he needs to shut down the Mingo Kids, get his dad to stop Rodrick from messing with his work, resulting in his grades falling 64%, have a good few weeks leading up to Manny's 6th birthday, and look for a way to get popular.
He knows that Patty would kill him if he tried to split them and the Mingo Kids up, But he tells the principal everything, and Patty gets tracked down, expelled, and sent to military school. The Mingo Kids slowly disband in the days following, going from 255 members on 31 May to completely disbanding on 17 June.
He then gets his dad to ground Rodrick every time he bullied Greg. Greg's grades rise 81%. Rodrick's grades also rise by about 10%.
He figures to be 156th popular, but rises 86 places once the Mingo Kids disband and another 55 places when he starts a band and beats Rodrick by 702 fans.
Greg gets another stroke of luck when, as he rises above Bryce Anderson (fell to #19 after the Mingo Kids disbanded) the most popular girl, Emma Ontario, gets dumped. He then gets in a race with Rowley to see if anyone could get Emma as a girlfriend before the first day of high school. On June 31, with 10 days until the summer vacation, Rowley is about to win, but is distracted by Holly Hills, which causes Emma to think he's crazy... which, when Bryce kicks Greg in the face, he is expelled as well as Patty, but Emma feels sorry for Greg and becomes his girlfriend,
Greg then tells Mom that he got a girlfriend, and Patty and Bryce are expelled. Rodrick was enraged that Greg beat him AGAIN.
During the summer vacation, Patty breaks in, trying to shoot Greg. Emma, around then, calmly calls the police, but then Greg reveals his greatest secret: He has a black belt (9th dan) in karate. He then uses it on Patty, who is arrested for breakin. once the police arrive.
On the last day of summer, Greg throws a "Exit Middle School" party, on the tall 2 decker school bus. He fitted a Xbox, PlayStation, TV, 30 games, bathroom, living room, tables, kitchen and EVERYTHING needed to turn it into a party home.
He goes to high school (9th grade, day 1) and finds that it is bigger. He settles down.