Many fans feel that Captain Jack (John Barrowman) has played out his story in Doctor Who, but what those Whovians forget is that one mystery remains, and it's Jack's first and greatest mystery. In Jack's very first story, The Empty Child, he mentions that he is missing two years of memories. He was a Time Agent and he woke up one morning to find that the Agency had erased two years of his memory. This violation caused him to quit the Agency and become a con artist. Jack states that he wants the missing memories back. Only he never gets them back. Surely Jack could return one last time to help uncover what the Agency took from him and find out why they did it once and for all? The answer to this riddle could be practically anything the producers wanted it to be. Whenever Captain Jack Harkness is concerned, the possibilities really are endless.