Arne Treholt is, in fact, a real person, which people probably know if those people are Norwegian. He was a member of the Norwegian Labour Party and, in 1984, was arrested and convicted of espionage and treason after being accused of passing confidential data to agents of the KGB during the 70s and first half of the 80s. The trial was sensational not just because it came at the height of Cold War paranoia, but because the evidence against Treholt was considered, by many, to be somewhat flimsy, if not totally non-existent. Accusations continue to be made, as late as a book published in 2010, that most of the damning evidence against Treholt was fabricated or planted by antagonistic intelligence organizations. Regardless of the questionable nature of the evidence, the politician was found guilty and sentenced to twenty years in prison, only eight of which he served before being pardoned.
As imagined by the movie, Arne Treholt was the commander of an elite, ultra top secret special force of ninjas who answered only to the king of Norway. After endlessly irritating Stay Behind, a anti-Communist black ops organization with close ties tot he CIA, Arne and his band of ninjas were either framed for treason or murdered.