Natalie Blake was a private investigator and former detective sergeant in 2008. She had a heart condition which caused her to be sacked from the police, after which she became a PI. She sought treatment at the Pharm for her condition and was investigating the New Eden research lab. She was possessed by the aliens running New Eden whilst she was at the Pharm (with whom New Eden were working). She faked her own death by burning her twin sister Naomi to death in a car. She then killed Conrad Fischer, whom she was dating, whilst he was making a webcast and stole Fischer's laptop with the New Eden codes in it.
However, she had no idea she had done these things because of her alien possession. She checked into the Cardiff Century Hotel and realised her actions, recording her last moments on a video hidden on her website. Soon after, she was killed in her hotel room by a Pharm assassin. (GAME: Torchwood Mission Game)