In a special two-part series, Fault Lines travels across Iraq to take the pulse of a country and its people after nine years of foreign occupation and nation-building. It's 2012, and US combat troops have withdrawn. The so-called Islamic State is still underground. How are Iraqis overcoming the legacy of violence and toxic remains of the US-led occupation, and the sectarian war it ignited? Is the country on the brink of irreparable fragmentation? Correspondent Sebastian Walker first went to Baghdad in June 2003 and spent the next several years reporting unembedded from Iraq. In this second part of a very personal series, he returns and travels from Erbil to Mosul and Fallujah, revisiting old friends. Can the ghosts of the past ever stop haunting the future?