Quite unusually for this kind of story, one of the main heroes is a Texas Republican D.A. and one of the main villains is a female defence attorney who worked for the Innocence Project. I guess the overall lesson could therefore be: it's complicated. But the immediate moral of the tale is clear: ensure you have a good lawyer. The style and format of the series closely follows what has clearly become a formula for "true crime" documentary series, but this is still a fairly adequate example.