The team are conflicted when Jack Harkness returns after his unexpected departure, but won't reveal where he's been. So, when an old acquaintance of Jack's arrives in the city and starts wreaking havoc in his quest to find something hidden on Earth, the team struggle to work out whose side Jack is really on.

Toshiko falls for a handsome soldier, trapped out of his time, who unwittingly holds the key to saving the world. With an old hospital haunted by ghosts from 1918, a crisis foreseen by Torchwood 90 years ago is about to reach its climax. Time zones are colliding and with life and death decisions to be made, will Torchwood be able to stop an explosive end for Cardiff?