Five years ago, Denmark was hit by terrorism when 22-year-old Omar el-Hussein attacked the Krudttønden community centre and Copenhagen's synagogue, and killed two people. The Danes were shaken and the country changed. What made a human being commit an inhuman act? Could the tragedy have been avoided? Questions that the survivors are grappling with. In the film, we time meet the many people who best knew Omar el-Hussein, and with new witnesses, confidential documents, police photographs and video surveillance footage, the film shows the harrowing course of events that led to the attack and sheds a new light on a dark chapter of Denmark's history.