A Dragon Arrives!Movie

On Jan. 22, 1965, the day before the Iranian prime minister is assassinated, a car drives up to a shipwreck. Inside the wreck, a banished political prisoner has hung himself and the walls are covered in diary entries, literary quotes, and strange symbols. Fifty years later, the evidence, including intelligence tape recordings, is found in a box. The contents attest to the fact that the inspector and his colleagues were arrested, but why?