Good Luck Charlie follows the Duncan family as they adjust to the surprise birth of their fourth child, Charlotte 'Charlie' Duncan. When parents Amy and Bob return to work, they enlist the help of their three older children—teenagers Teddy and PJ, and pre-teen Gabe—to help raise their new sister. The series is framed through video diaries created by Teddy, who records advice for Charlie to navigate the chaos of their family life as she grows up. Each episode centers on the comedic mishaps and relatable family dynamics of the Duncans living in Denver, Colorado. As the children navigate school, friendships, and romantic interests, they must balance their personal lives with the responsibilities of helping raise a toddler. The show is celebrated for its grounded humor and the genuine bond between the siblings, culminating in Teddy's signature sign-off at the end of every video: 'Good luck, Charlie.'