Why did the taxi crash on the autobahn in Vienna?

Who exactly were Besfort Y and Rovena, the mysterious couple who died after being flung from the back seat?

How was Besfort connected to the war in the Balkans? And why was his affair with Rovena clouded in jealousy and mistrust?

Who wanted them dead?

This is the story of the last forty weeks of their lives - a fever dream where love and obsession collide.