Charlie Chaplin in The Kid
Charlie Chaplin and Jackie Coogan starred in this 1921 comedy. It was the 2nd highest grossing film of the year and remains a classic.
The movie, Chaplain's first full length feature, told the story of a child abandoned by his mother who leaves a note to care for the boy and found by "The little tramp". For five years the little tramp cares for the boy.
The mother in the meantime becomes a wealthy star and does charity work among the poor, actually meeting her son but not recognizing him. When the boy becomes sick he is taken to the doctor who discovers that he is not the son of the tramp. The doctor shows the mothers note to the police and she offers a reward for his return.
After spending the night in a flophouse the owner recognizes the boy and steals him away from the tramp to claim the reward. The little tramp searches for the boy until he falls a sleep and the movie enters a dream. When he a policeman awakens him he is taken to the home of the woman. The kid recognizes the little tramp and he is welcomed into their home.