Brilliant opening to this final two-parter of the 2006 season when the Doctor takes Rose on the Time Lord equivalent of whale-watching: DRAGON-watching! Back to normality soon enough though, if anything around the Doctor can be called normal, as the travelling twosome drop in to pay a visit on Rose’s Mum Jackie.

Amazingly enough all is not well on 21st-century Earth, where ghosts are being sighted all over the world on some kind of regular schedule.  It’s been happening so long that people are no longer surprised or even bothered about it.  On the contrary, quite a few of them have even started to look forward to the visitations, including Jackie.

Having detected the ghosts’ origin by triangulating on a power source of tremendous intensity the Doctor flies the Tardis off to check it out, with Jackie in tow.  They land at Torchwood HQ, where the operatives are in charge of using a particle beam to open the rift that is allowing the "ghosts" through from another dimension.  Torchwood have also detected the Tardis’ arrival and are waiting to meet (and capture) the Doctor when he materialises.

Two of the operatives sneak off for a quick tryst in a cordoned-off area of the building and somehow become separated.  Threading her way through curtains of plastic sheets, Adeola comes face-to-face with…a Cyberman!

The Doctor is taken under guard to see Torchwood’s most prized alien artefact, which he immediately identifies as a Void Ship.  Capable of travelling in the space between dimensions, which is known as the Void to the Time Lords (or "Hell" to other races, the Doctor comments morbidly), this ship is even more powerful than the TARDIS, since it moves completely outside time and space.  It is the appearance of the Void Ship in our world which opened the space-time rift.  Despite their best efforts Torchwood scientists (including Mickey, who has somehow managed to escape from the parallel "Cybus" Earth) have been unable to analyse or penetrate the Void Ship, and don’t know what it contains.

Adeola has reappeared in the control room wearing a Cybus earpiece and behaving like a zombie.  One by one, she invites other operators into the plastic sheets to be overcome by the waiting Cyberman.  Once they are all converted, they switch the particle beam to full power and the ‘ghosts’ begin to fully materialise in our world.  They’re all Cybermen – a whole army!  But the Cyberman leader admits the Void Ship is not their technology.  They merely use it to hitch a lift between dimensions.  The Void Ship begins to open and five Daleks fly out.  The leader, a Black Dalek, cries "Location: Earth.  Lifeforms detected.  Exterminate!!"