The members of the Torchwood Institute, a secret organization founded by the British Crown, fight to protect the Earth from extraterrestrial and supernatural threats.

Captain Jack Harkness: [voiceover during second season opening] Torchwood: outside the government, beyond the police. Fighting for the future on behalf of the human race. The 21st Century is when everything changes -- and Torchwood is ready.
Captain Jack Harkness: [voiceover during first season opening] Torchwood: outside the government, beyond the police. Tracking down alien life on Earth, arming the human race against the future. The twenty-first century is when everything changes. And you gotta be ready.