Mrs. Brown thinks that she has the prettiest baby in the world, but everybody knows that it is a poor puny little girl with no claim to beauty. A doctor makes a great discovery in the form of a tonic to he placed in the baby's milk. Mrs. Brown gives the tonic to her baby and it starts to grow at a wonderful rate. The nurse takes baby out for an airing and while she is having a little flirtation it grows to be a plump three-hundred pound wonder and gets lost in the park. A diminutive policeman finds it and has his own troubles getting it home to its surprised mother and relatives.
—Moving Picture World synopsis