Will Smith, who has done nothing wrong, accidentally winds up in possession of something that's Secret, not because it's actually a state secret, but because it's dangerous to someone who's breaking the law (sound familiar?).
They proceed to use the vast powers of surveillance in public cameras, debit card access logs, and some tracking devices they plant on him to follow him everywhere. One day, he's a normal citizen and the next, he's a criminal though he's done nothing.
This movie speaks to the power of vast data and monitoring systems and how a very small handful of people can target and destroy anyone using these systems. This is why privacy advocates try as hard as possible to keep data systems from becoming too connected and fight human tracking.
