"Diary of a Wimpy Kid: The Long Haul" is the ninth book in Jeff Kinney's Diary of a Wimpy Kid series. In this installment, Greg Heffley and his family embark on a road trip across the country, which is supposed to be a fun family vacation. However, things quickly go awry, and the trip turns into a series of chaotic and disastrous events.

Greg deals with everything from wild animals to a pig that the family wins at a country fair, an encounter with a menacing family at a motel, and the general dysfunction that arises when the Heffleys are crammed into a van together for an extended period.

Like the rest of the series, "The Long Haul" is written in a diary format with Greg's signature humor and observations about life, family, and all the misadventures he faces along the way. The story captures the challenges and mishaps that often occur on family vacations, all told through the lens of Greg's witty and sarcastic perspective.