The Kid (1921)

An unwed mother who can't care for her baby boy leaves him in a limousine, with a note imploring whoever finds it to care for and love the child. After she leaves, thieves steal the limo and abandon the child in a garbage can. A tramp (Charlie Chaplin) comes across the baby and takes him in.

Five years later, Chaplin has become a glazier, while his adopted son (the remarkable Jackie Coogan) drums up business for his old man by cheerfully breaking windows in the neighborhood. The unwed mother has become a world famous opera singer, still haunted by the memory of her child. She does charity work in the very slums in which he now lives. Ironically, she gives a toy dog to little Coogan.

Chaplin and Coogan's close calls with the law and fights with street toughs are easily overcome, but when Coogan falls ill, the attending doctor learns of the illegal adoption and summons the Orphan Asylum social workers who try to separate Chaplin from his foster son. In one of the most moving scenes in all of Chaplin's films, Chaplin and Coogan try to fight the officials, but Chaplin is subdued by the cop they have summoned. Coogan is roughly thrown into the back of the Asylum van, pleading to the welfare official and to God not to be separated from his father. Chaplin, freeing himself from the cop, pursues the orphanage van over the rooftops and, descending into the back of the truck, dispatches the official and tearfully reunites with his son.

Returning to check on the sick boy, the woman encounters the doctor and is shown the note which she had attached to her baby five years earlier.