Strike Back is a British/American action and military television series, based on a novel of the same name by novelist and former Special Air Service (SAS) soldier Chris Ryan. The series follows the actions of Section 20, a secretive branch of the British Defence Intelligence service (DI), who operate several high risk, priority missions throughout the globe. The series began broadcasting on Sky1 on 5 May 2010, showing the first six-part series. After a second series was commissioned, it was announced that Cinemax would co-produce the franchise. The first episode of the ten-part second series, under the banner title Project Dawn in the United Kingdom, first aired on Cinemax on 12 August 2011. The ten-part third series, under the title Strike Back: Vengeance, began airing on Cinemax on 17 August 2012. On 3 October 2012, Cinemax and Sky commissioned a fourth series, which was broadcast on Cinemax beginning 9 August 2013. A ten-episode fifth and final season will air in 2015. Executive producer Andy Harries gained hold of the novel and pitched a television adaption to Sky, even though he had not read it. Sky commissioned the series as part of a e10 million commitment to adapt novels into original dramas following the successes of adapting Terry Pratchett's Discworld novels. Following Cinemax's participation from the second series, the series faced a re-imagining due to the absence of first series lead Richard Armitage, who was at the time filming The Hobbit in New Zealand. Before filming several cast members participated in bootcamp training by former SAS and Special Boat Service (SBS) officers. The series was filmed on location in South Africa, although parts of the second series were filmed in Hungary.