On the morning of 9/11, the Port Authority Police Department was the first uniformed service to respond to the attack on the World Trade Center. When the towers collapsed, thirty-seven of its officers were killed -- the largest loss of law enforcement officers in U.S. history. That afternoon, Lieutenant William Keegan began the work of recovery. The FDNY and NYPD had the territory, but Keegan had the map. PAPD cops could stand on top of six stories of debris and point to where a stairwell had been; they used PATH tunnels to enter "the pile" from underneath. Closure shares many never-before-told stories, including how Keegan and his officers recovered 1,000 tons of gold and silver from a secret vault to keep the Commodities Exchange from crashing; discovered what appeared to be one of the plane's black boxes; and helped raise the inspirational steel beam cross that has become the site's icon. For nine brutal months, the men at Ground Zero wrestled with 1.8 million tons of shattered concrete, twisted steel, body parts, political pressure, and their own grief. Closure tells the unforgettable story of their sacrifice and valor, and how Keegan led the smallest of all the uniformed services at the site to become the most valuable.