"Kiss Kiss, Bang Bang" is the first episode of the second series of British science fiction television series Torchwood, which was broadcast on BBC Two on 16 January 2008. The episode features a guest appearance from James Marsters as Captain John Hart, the former colleague and lover of the alien hunter Jack Harkness (John Barrowman). In the episode, John double crosses Jack's Torchwood team as part of a plan to steal a diamond from a woman who was murdered. Chris Chibnall wrote the episode with the knowledge that Marsters wished to appear in the series, and has written the part of John Hart "absolutely" for him. The episode was filmed in Cardiff in July 2007. "Kiss Kiss, Bang Bang" was seen by four million viewers upon its original broadcast, with an Appreciation Index of 84, and was met with generally positive reviews in both the United Kingdom and United States. Plot Jack, after finding the Doctor and witnessing the end of the world, returns to his Torchwood team, and shoots an intoxicated alien Blowfish involved in a hostage situation. During a murder investigation at a multi-storey car park where Rift activity has been detected on the corpse, Jack receives a surprise call on his vortex manipulator from the murderer: Jack's former lover, the Time Agent Captain John Hart. Jack joins him at a nightclub to catch up with him, and John accompanies Torchwood to the Hub. He tricks Torchwood into finding three cylindrical devices which he claims are dangerous bombs that need defusing. He believes they will triangulate the location of a diamond he stole off a different former lover. Torchwood split into three groups. Gwen and John search the docks. John paralyses Gwen and locks her in a crate, telling her that if she is not found in two hours, her main organs will stop working and she will die. Toshiko and Owen search a warehouse. John shoots Owen in the hip. Jack and Ianto search an office block. John pushes Jack off the roof when he realises the bombs are a confidence trick. John then takes a pyramid-shaped object from the Blowfish in the Hub's morgue. Gwen is saved by the team, while Jack survives the fall due to his immortality. Torchwood confront John, who discovers there is no diamond; John's former lover anticipated dying, and thus set a trap to kill her murderer. The device turns out