WPC Gwen Cooper is at the scene of a brutal murder, when the "special ops," known only as Torchwood, arrive. After witnessing the group bring the dead man back to life, Gwen goes in pursuit of this mysterious organisation, only to see weirder things than she could ever imagine existed. Soon after, she begins to regret giving in to her curiosity, when she meets Captain Jack Harkness.

It's Gwen's first day on the job, and it's not going very well. After accidentally releasing a mysterious gas from a comet that landed, a new type of alien is let loose on the streets - an alien that's addicted to sex. Torchwood must find the inhabited body, and prevent anymore deaths from the violent form of sex.

Captain Jack returns, as the Torchwood team reunite to fight a rogue Time Agent. The mysterious Captain John Hart is determined to wreak havoc, and needs to find something hidden on Earth. But with Gwen's life in danger, and cluster bombs scattered across the city, whose side is Jack on?

Jack calls in an old friend for a favour, none other than Martha Jones, as they attempt to stop a pharmaceutical facility that uses aliens in the hope of discovering a cure for all diseases.

Gwen finds the darker side of Torchwood when a teenager disappears, investigating why hundreds of people have vanished without a trace. Jack is obstructing attempts to find them, and the answer appears to lie in the Rift.