Black flies breed in large numbers in the Bronx, New York City, in the summer. The film is based on the 2008 novel 911 by Shannon Burke. The story takes place in New York City and tells the story of young paramedic Ollie Cross, who teams up with experienced doctor Rutkowski to re-examine the meaning of life and death and change his outlook on life in the face of the cruel reality of drugs, crime and violence.