Again, it's another movie about politics and the justice system in the States. Americans always put so much emphasize on the value of family. So, when Clyde lost his wife and sweet daughter (technically, he was watching his wife being raped and his little princess being taken to hell), the revenge already started at that point without him knowing it.
A typical engineer trusted the law to make sure that the justice was served. Unsurprisingly, Nike made a deal with Darby's lawyer to let the real killer walk away just like what many real-life lawyers would do.
What happens next is that Clyde took 10 years using his born technical gift to map out a revenge plan.
The most exciting part took place when Clyde was facing the judge he faced 10 years ago, Clyde made the judge look really damn bad by using his studying and the understanding of the law during the decade. The judge is actually a representation of the entire system.
The ending once again tells us a simple thing: life is all about making choices. None of these would have happened, if people made the right choice. You guys should go check it out. You not only see an outstanding film, but also learn lots of things.