A young African American falls into periodic spasms and chants a text that nobody understands. His troubled family seeks help. The text, recorded by a psychiatrist and deciphered by linguists, is found to be a corrupted family chant from the Yoruba of Nigeria. The doctor advises a trip to that ethnic region. The spiritual voices that have been summoning Otis finally bring him to the spot where his ancestor was enslaved over a century before. Two years...