While investigating reports of old music emanating from a derelict dance hall, Jack and Tosh find themselves transported back into the midst of the Cardiff Blitz in 1941. In this time period, the dance hall is playing host to a group of air force pilots who are enjoying their final day of leave -- and, much to Tosh's astonishment, one of them is named Captain Jack Harkness. While Jack forges an unexpected friendship with the man whose name he stole, Tosh searches for a way to return them to the present. And in both 1941 and the present day, the sinister Bilis Manger has his eyes on Torchwood...