Greg Heffley talks about how his mother does not like technology and smart phones, and is starting a petition to prevent the town from using electronic devices for a weekend. As his school year starts, he comments that he feels like he has "been stuck in middle school forever," and that he wants to change things up, so he signs up for the Homework Buddies program. At home, Greg's grandfather moves in with them after the rent is raised at his retirement home and his girlfriend breaks up with him. After Greg forgets to screw the toothpaste cap back on, his father Frank lectures him about how small things can lead to big consequences.

Greg hears about a school trip to a farm, which he decides to skip out on. His mother gets enough signatures for her petition, so the next day, Greg attends a park cleanup. He gets tired and runs away, then meets up with his Homework Buddy. A teenager doing community service follows them as well, and Greg gets him in trouble after pointing out that he stole some cookies.

Back at home, while his parents are away, Greg tries to put the toothpaste cap back on after brushing his teeth, but it falls down the drain. He loosens a pipe to get it, but forgets to turn off the water valve first, causing a puddle of water to leak downstairs. His grandfather tells him that they can buy paint and cover up the stain, but while on the road, he drives the wrong direction and the car runs out of gas. Greg accidentally moves the car, which falls into a ditch, and his parents arrive. He decides to go on the trip to get out of town and avoid facing punishment from Frank.

After arriving at the farm, Greg hears rumors about a deranged farmer named Silas Scratch who still wanders around the area. The kids struggle to adapt to their uncomfortable cabins, with some even trying to get sick and go home early