Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Authentic Boston, but the tale grows weaker by the minute

I was bowled over by the authentic Boston look, accents and the real people cast in this crime drama, based on a Dennis Lahane novel, directed by Ben Affleck. The beginning works extremely well, and the film seems to be over halfway through, but then takes a few more plot turns before the ending, which doesn't work for me. Casey Affleck is very good as the central character, and his accent is perfect because he grew up in Dorchester. I just thought the plot lost some credibility as it went on: have real police ever been involved in a kidnapping to try to save a child from neglect? I really doubt it. Otherwise, this is first-rate, and moves along without any dead space whatsoever. Extremely entertaining and watchable, despite the plot weakness.