The Kid Reporter (1923)

The 'secretary' of a busy newspaperman is revealed to be a cherubic small child, Baby Peggy. When a rich woman's pearl necklace is stolen, Baby Peggy's employer promises to make the reporter who cracks the case Editor-in-Chief. The little girl seizes the opportunity, and -- several disguises and chases later, with the grudging aid of the office-boy -- duly returns with the jewels to achieve promotion, with all the adults scurrying to serve her.