Inside the investigation that broke the biggest case of insider trading in history.

On the constantly evolving definition of insider trading and the lingering question of how inside traders should be punished.

The downfall of a Goldman Sachs director:

"Now from, for the last three or four, I mean four or five years, I've given him a million bucks a year, right?" says Rajaratnam. "Yeah, yeah," says Gupta, who doesn't appear taken aback at all by Rajaratnam's next remark: "After taxes. Offshore. Cash."

In an elaborate FBI sting to expose corruption, four agents pose as futures traders in Chicago. The plan works–if you don’t count the hundreds of thousands in taxpayer dollars the agents lost in the process.