Forty-seven is the name and number of a 14-year-old slave working on Master Tobias’s Georgia plantation in 1832. Forty-seven is also the narrator of Mosley’s young-adult literature debut, still alive almost two centuries later to tell of his fated encounter with 3,000-year-old Tall John from “beyond Africa,” who has arrived in a Sun Ship from planet Elle (where red and purple forests are populated by tiny, multi-colored men and women) in the guise of a young runaway slave. This boldly unusual blend of historical fiction, science fiction and fantasy has some powerful moments, such as when 47 is brutally branded by a sadistic fellow slave; and many heroic moments, such as when 47 and Tall John battle evil forces to keep them from mining the Earth’s green powder and destroying the planet. Mostly, however, this is a flawed, didactic exploration of the nature of freedom, juxtaposing the brutality of 19th-century American slavery with the society of a faraway planet where skin color is irrelevant because “behind all existence there is one great mind.” (Fiction. 12-16)