Teenagers PJ and Teddy and their younger brother Gabe are ordinary kids -- that is, until their mother gives birth to another child. The arrival of their little sister completely upends the household. When their mother returns to work after the birth of Charlie, the kids and their father must keep the home fires burning -- and keep Charlie out of trouble while she learns to sit up, crawl, walk, and run. Teddy, as the older sister, creates a personalized video diary for Charlie, adding a piece of wisdom for her little sister in each episode.