Who Are You?

The Doctor arrives in 1851 London on Christmas Eve and everything seems peaceful with the preparations for Christmas in full swing. Then he hears someone in distress calling out for him. To his surprise he then encounters a man who calls himself 'The Doctor'!

But can this really be a future incarnation of The Doctor? If so then his future self seems to have no memory of past incarnations and has a suspiciously conventional sonic screwdriver. Nonetheless, the Next Doctor and his companion, Rosita, have uncovered Cybermen activity in Victorian London.

It seems the Cybermen are planning to attack the city with a human ally, a Miss Hartigan. The Doctor follows the Next Doctor to a house of a dead man, the Reverend Aubrey Fairchild, where they search for clues to what the Cybermen are planning. Here the Next Doctor begins to regain some of his lost memories. Then when The Doctor finds a pair Cybermen data storage devices, called 'infostamps', the Next Doctor remembers he was holding one the night he lost his memory.

Jackson Lake and Rosita

The Cybermen then attack the house, but before they can kill both 'Doctors', the Next Doctor kills them with an electrical charge projected from one of the infostamps giving The Doctor the answer to why the Next Doctor has lost his memory.

Realising what has happened, The Doctor explains that the Cybermen have escaped from the Void (following the Battle of Canary Wharf) when the walls of the universe were weakened in ‘a greater battle’. On arriving in the city the Cybermen came upon a man named Jackson Lake, the first person to disappear, attacking him and his wife. In the confusion, Lake destroyed the Cybermen with an infostamp (one containing information on The Doctor gleaned from the Daleks) but it backfired, overwhelming Jackson Lake's mind with information about The Doctor – so making him believe he is The Doctor.

A Cybershade

The Doctor then discovers that in the city men have been murdered and children have disappeared – all at the hands of the Cybermen and Miss Hartigan - who the Cybermen have offered her liberation. The Doctor confronts the Cybermen and manages to convince them that he is their foe. Miss Hartigan orders the Cybermen to delete the pair, but Jackson Lake appears and destroys the Cybermen with another infostamp, allowing them to escape. A furious Miss Hartigan announces that ‘the CyberKing will rise tonight!’

When Jackson Lake reveals that he and his family were attacked at their new house The Doctor realises it may lead to the Cybermen's base. There, they find a Dimension Vault - stolen Dalek technology that allowed the Cybermen to escape the Void. In the Cyber-base, the captive children are working to generate power to allow the CyberKing - a giant Cyberman-shaped robot ship - to ascend.

As The Doctor, Rosita and Jackson Lake evacuate the children, including Jackson's son who was abducted when he was attacked, Miss Hartigan is betrayed by the CyberLeader and 'converted' to the CyberKing. However, she proves too powerful to control, and uses her new powers to destroy the CyberLeader.

Two Doctors

As the CyberKing emerges from the Thames, and begins to lay waste to London, The Doctor uses Jackson Lake’s ‘Tethered Aerial Release Developed In Style’ (TARDIS for short) - a gas balloon - to confront Miss Hartigan and the Cybermen in the CyberKing. He however, is unable to convince her to stop and so is forced to use another infostamps to sever her connection from the CyberKing.

Realising what she has become, Hartigan screams in horror destroying the Cybermen and herself. Before the CyberKing can collapse on the city, The Doctor uses the dimension vault to transport it into the Time Vortex – so saving the city.