The film is based on the true story of Natascha Kampusch, a 10-year old girl and her eight-year ordeal being kidnapped by Wolfgang Přiklopil.
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In late 2012, there were concerns about Campbell-Hughes' drastic weigh-loss for the film, however she stated in an interview in the Evening Standard that she wanted "to suffer as much as she - Kampusch - did".
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The film was writer Bernd Eichinger's last film before his sudden death, and Martin Moskowicz, head of TV and Film at Constantin Film, and Ruth Toma (Gloomy Sunday) took over.