"Jack and Tosh go to investigate a possible breach in time: 1940s music has been heard from an abandoned dance hall. They find themselves back in time, in 1941, at a dance for service personnel. They meet Captain Jack Harkness, the man whose identity Torchwood's Captain Jack stole after his death, which will occur the following day during a training exercise."
Back in 1941, the real Captain Jack reveals he is attracted to Torchwood's Jack, and the two share a brief awkward moment holding hands. Torchwood's Jack asks to go somewhere else but Captain Jack says "No, you've told me all I need to know".
Later Captain Jack invites Torchwood's Jack to dance. The rift opens as the pair are about to kiss and Torchwood's Jack pulls away, saying it is his duty to go. However, on his way over to Tosh, he stops and turns back to the real Captain Jack. They share a passionate kiss, to the further astonishment of the other dance hall guests, before Captain Jack and Tosh return to the present day. There is a tear on Torchwood Jack's cheek. In the present day Gwen is there to greet them and while Gwen and Toshiko are hugging and laughing, Jack stares at the old dance hall looking devastated. Back at the hub Toshiko and Jack drink and toast "To Captain Jack".
Every pane of glass that your pebble taps,
Negates the pains i went through to avoid you,
And every little pat on the shoulder for attention,
Fails to mention i still hate you.