An entertaining, lively and teasing thriller. In early December the meteorologists raise the alarm. The newspapers have been writing about nothing else for several weeks: 'Extreme summer goes on – and on and on!' It's not only in Norway that the temperature continues reaching new heights. Temperature records and heat-waves are reported from all of the Northern Hemisphere.
At the same time, it is abnormally cold in the Mediterranean and in South-East Asia. Something is happening, but what? The temperature changes don't look promising for Norway. The winter Olympic Games are due to take place in Tromsø, but where's the snow?
Hanna reckons that something is not as it should be and discovers that somebody is holding winter as a hostage. Together with Oscar the petty thief she traces the evil plans which lead right up to the government and multinational villains.