"Somewhere out there in that chaos of darkness and light, of science and protons, of gods and stars and death... somewhere there's an answer."
The Torchwood Institute was founded by Queen Victoria in 1879 to protect the British Empire against the threat of alien invasion. By 2008, all that remains of the organisation is a small team based in Cardiff. And now, following the tragic deaths of two of their colleagues, the remaining three - Captain Jack Harkness, Gwen Cooper and Ianto Jones - have to protect the human race against another unknown force from the darkness.
Martha Jones, ex-time traveller and now working as a doctor for a UN task force, has been called to CERN - the world's largest particle physics laboratory in Geneva - where they're about to activate the Large Hadron Collider (LHC).
The LHC is a particle accelerator which has been built deep underground in a 27km tunnel under Switzerland and France. Once activated, the collider will fire beams of protons together, recreating conditions a billionth of a second after the Big Bang - and potentially allowing the human race a greater insight into what the Universe is made of.
But so much could go wrong - it could open a gateway to a parallel dimension, or create a black hole - and now voices from the past are calling out to people and scientists have started to disappear...
Where have the missing scientists gone? What is the secret of the glowing man? What is lurking in the underground tunnel? And do the dead ever really stay dead?
Afternoon Play: Torchwood 'Lost Souls'
BBC Radio 4, 2.15pm, Wednesday 10 September