Spectral figures are appearing all over the world, leading many to believe that they're the ghosts of the dead. Suspicious, the Doctor follows their trail to the London headquarters of the enigmatic Torchwood Institute. Led by Yvonne Hartman, Torchwood's remit is to deal remorselessly with alien incursions on British soil. But Torchwood itself has been infiltrated by the Cybermen, who have established a bridgehead between dimensions using the breach caused by a Gallifreyan Void Ship. The Void Ship is now hidden at the top of Torchwood Tower -- and concealed aboard is something even more terrible...