There he becomes a member of Torchwood , a British organization dedicated to combating alien threats .
As a consequence of his death and resurrection in the 2005 Doctor Who finale , Jack becomes immortal and is stranded on 19th - century Earth .
There Jack becomes a member of Torchwood , a British organization dedicated to combating alien threats .
As a consequence of his death and resurrection in the 2005 Doctor Who finale , Jack becomes immortal and is stranded on 19th - century Earth .