Just before Christmas, Sonny Jim learns the awful truth that there is no Santa Claus from some of the older boys in the neighborhood and is heartbroken. In vain Daddy Jim and Mother Dear try to argue with the boy; he will not be comforted. Determined to prove the truth for himself, Sonny sits up the night before Christmas in a big chair by the fireplace, and falls asleep. He dreams that a big, gruff, cross-looking Santa comes down the chimney and carries him in his auto over the rooftops to the great throne room of King Santa Claus himself, who reprimands Sonny severely for doubting his existence. He then introduces the boy to the City Santa, who is sufficiently thin to get down the steam pipes, and various other interesting people, then he is sent to Father Time, who lives in a weird cave. Father Time sadly tells him he must take away his youth, as only the old people do not believe. Sonny sets up a yell, but it does no good, the old gentleman places him underneath a big machine, and he grows and grows until he is a great big man with a long white beard and grotesque features. Just as he regains normal size, Sonny wakes up to find his stocking filled with toys and good things, and with a happy smile he tells his dog, Toto, "never to doubt Santa Claus."
—Moving Picture World synopsis