The subsets of filmgoers likely to fall for the wonderful “Searching for Sugar Man” include the following: People who like music. People who watch movies.

Also: People who appreciate a good mystery. People who respond to stories about second chances, and who realize the public isn’t always right the first time, and that there’s more than one public.

Sixto Rodriguez is the subject’s name, and when this enigmatic Detroit singer-songwriter started gigging around town, once upon a time in the 1960s, he was known simply as Rodriguez. His recording career was brief and promising — but went more or less nowhere. There were rumors of an outlandish onstage suicide that fed the Rodriguez myth. But what became of him, really?

“Searching for Sugar Man” begins a long way from Detroit: along the sunny coast of Cape Town, South Africa, where the filmmaker, Stockholm-based documentarian Malik Bendjelloul, first heard about Rodriguez from the owner of a Cape Town record shop called Mabu Vinyl.

Years earlier, Rodriguez had slipped into stateside obscurity and/or death-shrouded myth. Bootleg copies of Rodriguez’s albums were discovered by anti-apartheid citizens of South Africa. Turns out the man from Detroit really was the voice of a generation, heard more clearly abroad than at home.

That’s material enough for a good music-soaked documentary, but “Sugar Man” has an even better story up its sleeve, chronicling the run-up to the triumphant 1998 concerts Rodriguez gave in South Africa.