To help their unemployed father make ends meet, Edith and her twin sister Grace work as seamstresses . An invalid, Grace falls prey to the temptations of Chinatown opium and becomes an addict, a condition worsened by a misguided physician who prescribes morphine to ease her pain. When their father strikes oil, the family enjoys a new prosperity and the sisters meet the eligible Jack Herron, a fellow oil prospector. To Grace's shock, Jack falls in love with Edith and in her jealousy, Grace tells Jack that Edith, not she, has a drug problem. Hinting that her sister will soon need more morphine, Grace arranges for a dinner in Chinatown with the couple. While her sister and Jack dance, Grace slips away to an opium den. Edith follows her, but ends up in the wrong den and is arrested in an ensuing drug raid. After he bails her out of jail, Edith takes an angry Jack to search for Grace and stumbles across her half-conscious body lying in the street. The truth about the sisters is revealed, and after sending Grace to a sanitarium in the country, Jack and Edith are married.