Investigating an abandoned dance hall amid rumours of ghostly music, Jack (John Barrowman) and Tosh (Naoko Mori) find themselves slipping through Time into 1941, when the dance hall was full of servicemen. Jack meets the real, original Captain Jack Harkness (Matt Rippy) from whom he stole his name. He will die the following day in a training exercise. Jack and Tosh need to open the Cardiff Rift to get back and Tosh tries to leave instructions for the Torchwood team, back in the future. Jack learns the other Jack is attracted to him, though that was not acceptable in those days. Jack hints that the other is not long for this world.
In the present, the team realizes that Jack and Tosh are missing, because they have photographs from the period. Ianto (Gareth David-Lloyd) insists that opening the Rift could destroy the city, but Owen is dying to do so, because he has plans to fetch his love Diane Holmes back from that period. The team meets the owner of the dance hall, Bilis Manger (Murray Melvin). They don’t know it, but he is also back in 1941 and is trying to change Tosh’s messages for the team, so he can get through himself.
Jack places the Rift Key in a clock in Manger’s office, along with Tosh’s equations, and Owen finds them in the present. Ianto pulls a gun on him and actually shoots him, but Owen goes ahead and opens the Rift. Shocking to everyone, Jack and Jack dance together and the Rift opens. Jack kisses him and he and Tosh step through. Manger is pulled along behind them. Back in the Hub, they toast the late Captain Jack Harkness.
Jack’s first appearance in Doctor Who was during the London Blitz, three and a half months later than the dance hall events. Jack’s safe password is Rhea Silvia, who gave birth to Romulus and Remus after being raped by Mars. Toshiko’s grandfather was persecuted during World War II, but one grandfather worked at Bletchley Park, so mathematics obviously runs in the family. There are at least three Captain Jacks alive at the same time, though one of them is a frozen cadaver. Bad Wolf is among the graffiti on the wall at the dance hall. The episode is filled with great World War II songs and jazz instrumentals. In the DVD extras, John Barrowman sings “Anything Goes.”
Getting Jack and Tosh back sets off a chain of events that threatens the city in the next episode. Owen is flirting with Tosh now. Apparently, Jack’s original name in the 51st Century was Javic Piotr Thane. In 2008, John Barrowman got in trouble for exposing himself and lost a Doctor Who comic-book gig as a result. On the other hand, he was asked to bare all during the filming of Doctor Who, so it should say, “exposing himself without permission.” It comes as no surprise that, in this episode, Jack meets and falls in love with himself. Kind of inevitable. The episode was nominated for the 2008 Hugo Award.