Plot summary
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 Jack 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 to be a bomb which attaches itself to the murderer of the bomb's owner, which is John, and begins a ten-minute countdown.
Unwilling to die, John handcuffs himself to Gwen and swallows the key in order to force Torchwood to remove the bomb. Gwen formulates a plan to use the Rift at the car park to contain the explosion, but at the penalty of her own life. Jack and Owen catch John and the rest of the team at the car park where John arrived and inject him with the team's DNA, thus confusing the device into detaching from John. Jack throws the bomb into the Rift where it detonates. John then regurgitates his key to free Gwen and agrees to leave. Before leaving, John tells Jack that he found Gray.
Credits
Adapted from Wikipedia contributors, Kiss Kiss, Bang Bang (Torchwood). Narrative and paragraph formatting adjusted; illustrations, reference markers and non-story material omitted.