Prologue
There was Jack. There was Gwen. There was also Ianto, Owen & Tosh. They made up Torchwood 3, the Cardiff, Wales division of Torchwood. Torchwood 1 was London, England & Torchwood 2 was Scotland, somewhere no one was really sure where was. Torchwood 4 was missing.
Back to the story of Torchwood 3. It wasn't a big complex organization, made up of five members who worked in the Hub (a giant base under the tower in the Roald Dahl Plass) to control the flotsam & jetsam that drifted through the rift into Cardiff. The rift itself was created long ago in the past when a weak spot between dimensions was opened then exploded. The five members thought they did okay despite their small numbers, & none of them really needed or wanted a sixth member.
Oh well, things like that can just happen without you choosing.