La Diagonale Alekhine tells the last seven years of former world chess champion, Alexandre Alekhine (1892-1946). Born in Russia, noticed for his gift at the age of 12, crowned world champion in 1927, naturalised as French in the same year, for a while Alekhine played his life like his games: winning every time. But in 1939, while in Buenos Aires, war caught up with him. Drafted into the French army, and summoned back to Paris, he returned home only to witness the collapse of his adoptive country. As he attempted to set out for America, he drew the attention of the occupying Germans, and became their hostage. For the new masters of Europe were too happy to have him at their beck and call, and to harness his fame and reputation. He collaborated, befriended Frank and Goebbels, and took part in the Reich's tournaments. The king became a pawn. One by one, his key wins escaped him: first his wife Grace, then the most talented of his rivals, starting with the persecuted players of Jewish descent, such as Spielmann, Rubinstein, and Przepiórka. When the war was over, he found himself alone, cornered, and finally exiled to a Portugal suffering under Salazar's dictatorship. It was there that the world champion would play his last game.