In 1986, Swedish Prime Minister Olof Palme is shot on a busy street in Stockholm. Decades later, the discovery of boxes hidden inside a storage facility leads one man to believe the answers to the murder lie buried in the forgotten files.

As the investigation continues, a picture emerges of Prime Minister Olof Palme's enemies as he walked a tightrope between the United States and the Soviet Union at the height of the Cold War.

Following Larsson's trail, Jan Stocklassa is led to South Africa, and a surprising motive is revealed. Certain that Larsson had uncovered the truth, Jan speaks to a former South African intelligence operative who admits to attacks on European soil.

As Jan Stocklassa pieces together the loose strands of Larsson's investigation, his path becomes more dangerous. Jan passes along the information he's gathered to the official investigation team, and suddenly Swedish police call a press conference.