1917. War or no war, monied Europe continues to feel the need for winter sunshine. Gustav Oscarsson and Katya Olovanova, two trembling swallows from the frozen North, fly south to bask in the warmth of the Riviera - she from the forests round Moscow, he from a narrow squeak in Oslo. Gustav brings Katya back to Oslo as a bride. Now, Oslo observes, both Oscarsson brothers have fine wives; Charlotta, pretty, transparent, elegant, controlled; and the tempestuous Katya, whom Oslo society admires with a salacious shudder - the Bolshevik's massacre of her family in the forest hanging about her like a shadowy blood mist. When Katya vanishes in San Francisco, Charotta is left with the pieces - and with the daughter, the second Katya, echo of the first, who burns as brilliantly as her mother, two comets on an inevitable parabola of destruction. As Norway awaits the arrival of the Germans, suffers the humiliation and deprivation of being occupied, and tries to come to terms with a post-war world, the Oscarssons face death, scandal and tragedy. And would any of this have happened if Katya had not been leaning on that balustrade in Riva del Garda in 1917?.