After a home invasion results in the death of the invaders, Torchwood suspects that one of the victims is an alien posing as an ordinary human -- and harboring the threat of an invasion.
Gwen and the team find a crashed van loaded with alien meat, with a connection to Rhys's transport company. Meanwhile Rhys decides to investigate the cargo himself.
Torchwood is infiltrated by a man with the ability to rewrite the team's memories with a touch. But the process has side-effects with the memories of Gwen and Jack's loved-ones.
Martha Jones visits Torchwood to help investigate a serial killer who is using human bodies to breed alien parasites, leading her to a cutting edge pharmaceutical company hiding a big secret.
Jack uses dangerous technology to bring one of his team members back from the dead, opening the door to a creature from the darkness beyond that preys on life.
Owen struggles to continue on in his life after death when he is temporarily relieved of duty, and makes use of his unique new abilities to infiltrate the home of a wealthy collector of alien artifacts.
An old friend of Gwen's convinces her to investigate the disappearance of a teenage boy. But she is not prepared for the evidence that Jack is involved in the disappearance.
Jack, Tosh, Ianto and Owen are trapped in the rubble of a collapsed building after an explosion, prompting them to recall the paths that their lives have taken to this point.
John returns, takes Jack captive and launches an attack on Cardiff, pushing Jack into an unexpected reunion with his lost brother -- while Gwen and the team fight to save the city from complete destruction.
