It`s summer vacation, the weather`s great, and all the kids are having fun outside. So where`s Greg Heffley? Inside his house, playing video games with the shades drawn. Greg, a self-confessed "indoor person", is living out his ultimate summer fantasy: no responsibilities and no rules. But Greg`s mom has a different vision for an ideal one packed with outdoor activities and "family togetherness". Whose vision will win out? Or will a new addition to the Heffley family change everything?