Ace Harlem was an African-American police detective who operated in an unnamed American city (most likely New York City). He was an observant, skillful detective with a track record that earned him the respect of the city's African-American community. He was a strong believer in justice as an innate force in the universe, that, one way or another, anybody who embarks on the life of crime will eventually suffer the consequences. He came into conflict with the professional criminal, Charm Root.