It all began through Sonny Jim's childish love for the make-believe. He wants to be a real postman, so when Daddy Jim gives him a letter to post, a most important business letter. Sonny trudges oft with it to the barn, where he very importantly deposits the missive in the oat bin. because it makes such a splendid make-believe letter box. In the same way he disposes of Bridget, the cook's, letter to Patrick, the iceman, in which she accepts his ardent proposal, and the letter of pretty Aunt Alice, wherein she curtly refuses her suitor, Peter, because of a trifling quarrel. All unconscious of the mischief he has wrought, the little postman pursues his untroubled way, but Daddy discovers a big business opportunity has been lost. Bridget waits in vain for her lover, and Peter, not hearing from Alice, believes himself forgiven and, jumping into his car, makes all speed to Daddy Jim's home, where Alice is staying. It looks like serious trouble all around, but it so happens that Peter really is forgiven by Alice after she has thought it over. Patrick is struck by Peter's auto and carried to Daddy Jim's home. He is not seriously hurt and after he and Bridget settle their differences, they decide to get married. Alice and Peter are reunited and also decide to become man and wife. But this is nothing to the joy exhibited by all, when, through a newspaper item, it is discovered that the business deal into which Daddy Jim had contemplated going, is a fraud. Had Sonny mailed his father's letter, Daddy Jim would have been ruined. So the little angel unawares is forgiven and made much of. instead of receiving the promised spanking from Daddy. Shortly afterwards, all, even Toto the dog, depart for church to attend the double wedding of Alice, Peter and Patrick and Bridget.
—Moving Picture World synopsis