Having survived the bombing attempts by Captain John Hart (James Marsters) in the last episode, the Torchwood team splits up to examine four events of Rift activity. Jack (John Barrowman) returns to the Hub and finds John waiting for him. John shoots him and before he can revive takes his weapons and chains him up. John takes him to the top of Cardiff Castle and makes his companions watch as he sets off bombs throughout the city. Then he transports Jack and himself back to Cardiff in 27 AD. Jack’s long lost brother Gray (Lachlan Nieboer) arrives and stabs Jack, then forces John to dig a grave. John has a bomb bound to his skin and is acting under duress. Filled with hate for Jack for abandoning him as a child, Gray buries him alive for all eternity. John drops a ring into the grave.
In the present, Gwen (Eve Myles), her husband Rhys (Kai Owen), and her friend Officer Andy Davidson (Tom Price) help organise the city. Gwen finds John at the Rift. John convinces her that he was forced to do what he did. He tells Tosh (Naoko Mori) to search for the signal from the ring, but they are unable to find it. They find Weevils blocking access to the Turnmill Nuclear Power Plant, which is heading for meltdown. But the Weevils worship Owen, who is undead, and he is able to enter the plant. Rhys and Andy seize Weevils attacking the police station and Gwen, Ianto (Gareth David-Lloyd) and John put Weevils in the Hub lockdown, but they are all locked in by Gray.
Gray shoots Tosh, mortally wounding her. She crawls to her communicator. Gray hears banging in the Hub and Jack appears out of the Morgue. Torchwood had found him in 1901 and put him in cryogenic storage so he wouldn’t meet himself. Gray refuses to accept Jack’s apology and has to be sedated. Other Torchwood members are freed. Tosh, weak from blood-loss, tells Owen how to control the nuclear meltdown, but a power surge traps him. Tosh and Owen share a tearful farewell and die. Jack places Gray’s body in storage. He consoles Gwen, distraught at Tosh’s final message.
Jon Hart dances to a song called, “I lost my heart to a Starship Trooper.” He found Gray in the Bedlam Outlands. Jack is 2100 years old. Tosh speaks of having covered Owen as a medic one time because he was hung over. This is to explain why Naoko Mori played a doctor in an episode of Doctor Who. Tosh and Owen are wonderful and heartbreaking in their farewell. It was thought the series would continue for a third season, but it did not. There were, however, two mini-series.