In Part 4 of the Meltdown series, investigators begin to sift through the meltdown's rubble. Meet the Dubai leaders who pretend the crash never happened, the Wall Street golden boys charged with fraud, a congresswoman who wants to jail the bankers, and the world leaders who want to rethink capitalism. Also profiled is City Boy, a notorious and anonymous London columnist who uncovered widespread immoral and even criminal behaviour by some of the city's wealthiest traders, including revelations of everyday insider trading. The big question on everybody's mind: could it all happen again?