In the midst of a warm and bustling summer, Greg Heffley finds himself trapped in a myriad of problems while trying to avoid boredom. It all begins when his mom decides it's time to enjoy some free time outdoors, and of course, that’s not on Greg’s wish list. He, a boy who prefers the comfort of his home and his video games, must deal with the summer plans his family has in mind, which include activities ranging from bike rides to camping.
What should be a summer of relaxation turns into a series of misadventures. Greg decides this is the perfect opportunity to impress his crush, Holly, so he tries his best to be the cool guy. But his strategy soon becomes complicated when his brother, Rodrick, enters the scene and starts wreaking havoc. As things spiral out of control, Greg also gets caught up in family chaos, which includes the arrival of a new dog, a series of summer jobs, and the looming threat of having to attend a camp he definitely doesn't want to go to.
With his characteristic humor and a bit of clumsiness, Greg navigates the madness of summer while learning some valuable lessons about friendship and family. All of this culminates in an ending that is as unexpected as it is hilarious, sure to leave a smile on the faces of all viewers.