With extraordinary access to the Office of the Chief Medical Examiner (OCME) in New York, this documentary tells the story of one of the world's largest forensic recovery operation after America's worst terrorist attack in 2001. To date, almost 22,000 individual pieces of human remains have been recovered from the debris. Scores of scientists, specialist machinery and cutting-edge DNA identification techniques have been employed and more than 1,600 victims have been identified. However, of the other 1,115 there is currently no identifiable trace. Their families have no closure, no fragments of their loved ones to bury. The team at OCME continue to push the limits of science in their painful and painstaking work, but now the search for the final victims has become urgent. A decision has been made to transfer the 8,000 unidentified remains to a specially built repository next to the new 9/11 Memorial Museum at Ground Zero. We follow the team as the latest phase of DNA testing draws to a close, and many families are left to wonder if there will ever be further ways to test the outstanding remains. The process is also followed from the other side – from the point of view of the families who have the OCME to thank for succeeding in identifying their loved ones. Geoff Campbell, an executive at Reuters, engaged to an American, was at the North Tower to attend a conference on 9/11. His Sussex-based family are one of several who have had numerous body parts returned to them over the years. The last piece, the sixth, was only identified in December 2013. Each time a piece arrives, Geoff's brother Matt, his mother Maureen and the family are faced with the upsetting ordeal of their grief being reignited once again. Firefighter Jack Fanning was in the vicinity of the North Tower when it crashed to the ground. Only his badly damaged helmet was ever found. With nothing else left of him, his daughter Jacqueline still questions what happened to her dad on that day and