The series follows two teenagers, Teddy Duncan (Bridgit Mendler) and Paul James (P.J.) Duncan (Jason Dolley), and their 10-year-old brother, Gabe Duncan (Bradley Steven Perry), whose parents enlist their help when they return to work after the birth of their fourth child, Charlotte, aka Charlie. With their parents juggling full time careers, the older Holliday siblings pitch in, getting very familiar with baby formula, burps, clothes, and babysitting while navigating typical teenage life. In each episode, Teddy creates a personalized video diary for Charlie. Each video will chronicle Teddy