Its summer vacation, the weathers great, and all the kids are having fun outside. So wheres 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 Gregs mom has a different vision for an ideal summer . . . one packed with outdoor activities and family togetherness.

Whose vision will win out? Or will a new addition to the Heffley family change everything?