Recap: Torchwood S1 E3 "Ghost Machine"

Owen sees the dark side of sex... rape.

Bernie: (to Owen after wearing down from being chased) Don't hurt me, I've got asthma!
Owen: I'm not gonna hurt you. I'm gonna bloody kill you!!
Owen viciously confronts a petty criminal after chasing him for 2 minutes

We join our team In Medias Res as they chase down a fleeing suspect. Tosh is certain the miscreant is the source of the alien reading they're receiving. Unfortunately, Gwen only gets so far as retrieving his hoodie. Fortunately, there's an object in his pocket which is in fact the source of the alien reading. Gwen finds the device and activates it. Through the device, she sees a vision of a young boy dressed in period clothes wandering through the train station.

From the train tag Gwen saw on the boy, Torchwood is able to track him down to his current status: as an old gentleman living in Cardiff. He was left alone after having been evacuated from London when he was just a boy during World War II. Turns out the alien device is a "quantum transducer", a device that allows the user to see events spurred by strong emotion. The scene Gwen saw was brought on by the immense fear he felt at being alone.

Deciding the device is dangerous, Torchwood sets out finding the original suspect they were chasing to learn where he got it. Returning to the scene, this time Owen uses the device and sees a vision of the 1960s, where a young woman, Lizzie Lewis, is raped and murdered by a suitor getting a little too rough with her. Owen feels her incredible fear and despair — a bit of a shock for him, seeing as he drugged and raped a woman and her boyfriend just two episodes ago (well, not exactly - fraudulently sexed them, maybe?) — and decides to bring her murderer to justice. Despite the rest of the team claiming that the case has gone cold and no good will come of this investigation, Owen tracks down the murderer, Ed Morgan. Understandably, Mr Morgan has no interest in discussing the incident.

During this investigation, Owen finally corners their original suspect, one Sean Harris. Sean tells Owen and the rest of Torchwood that he saw the vision of Lizzie and Ed also. He says he got the device from inside a tin he stole from an old lady, which turns out to be full of benign alien stuff that fell from the Rift. He also offers Torchwood "the second half" of the device. They put the device back together and Gwen activates it, seeing herself nearly hysterical with blood covering her hands and holding a knife. Sean says that when he used that half, he saw himself die on the road outside his flat.

The team puts together that Sean used the vision of Ed Morgan to blackmail him and theorisse that Sean's future death will be at the hands of Ed, paranoid and depressed. Both men are tracked down to Sean's flat. Gwen manages to disarm Ed, averting the future Sean saw, and to talk down Owen when he, still traumatised by witnessing the rape, vengefully threatens to kill Ed. But Ed, in a fit of depression, deliberately walks onto the blade Gwen's holding, fulfilling her vision. Poor Gwen is drenched in his blood, and just... stares. The device is placed in the secure archives in the Hub, where no one else can be traumatised by it anymore.