They call it "Pulse" - a radio signal which has puzzled the world for 40 years. But now Toshiko Sato has solved it.
She's uncovered a message which leads her to Russia, and into an uneasy alliance with the KVI - the Russian equivalent of Torchwood. Toshiko needs to get into Zone 10 - a frozen wasteland which officially doesn't exist.
An intergalactic war was once fought in Zone 10. And it turns out there's a survivor.
Torchwood contains adult material and may not be suitable for younger listeners
Written By: David Llewellyn
Directed By: Scott Handcock
Naoko Mori (Toshiko Sato), Krystian Godlewski (Maxim Ivanov), Ella Garland (Anna Volokova), Geoffrey Breton (FSB Agent)
Producer: James Goss
Script Editor: Steve Tribe
Executive Producers: Jason Haigh-Ellery and Nicholas Briggs