A Knock at the Door

The Doctor takes her three travelling companions; Graham O'Brien, Ryan Sinclair and Yasmin Khan to witness Mary Shelley gain the inspiration to write Frankenstein.

At the Villa Diodati on the shores of Lake Geneva in 1816, Lord Byron has gathered with Mary Godwin, her infant son William and her future husband Percy Bysshe Shelley, Mary’s sister Claire Clairmont and physician John Polidori. With stormy weather outside, the group challenge each other to come up with the scariest story they can imagine. Just as they start there is a knock on the door and they find The Doctor, Graham, Ryan and Yasmin asking to come inside.

After they are welcomed, The Doctor takes her travelling companions aside, reminding them that when Mary gets her idea for the story Frankenstein during this night, they must not mention any of this to her or her friends as they witness the moment of its creation.

Arrival at the Villa

However, soon after they arrive Percy goes missing and when they check his room, they find the walls covered in gibberish. As everyone in the villa searches for him, strange events start to occur in the villa, including seemingly-shifting portions of the villa's structure and Graham even sees a ghostly woman and a child.

Lord Byron suggests it is a ghost that haunts the villa but The Doctor suspects something more is amiss, and attributes the shifting structure of the villa to a security system that is either trying to keep them in the villa or is trying to prevent them from finding something in the villa.

Mary Godwin

The group then sees an apparition outside which The Doctor recognises as a being that has been moving through time. The apparition soon resolves into an incomplete, badly damaged Cyberman.

On witnessing the arrival of the Cyberman, Graham, Ryan and Yasmin remind The Doctor of Captain Jack Harkness's warning of the ‘Lone Cyberman’ and not to give it what it wants. But she angrily orders them not to follow her, and insists that they stay and protect Lord Byron, Mary and the others, before heading off to confront the Cyberman.

She discovers that the Cyberman, as well as being damaged, is low on power. The Doctor learns the Cyberman had been called Ashad, and it had been sent back in time to look for the Cyberium, a liquid metal with the collective knowledge of the Cybermen.

Ghosts?

The Cyberman has time travelled to 1816 and eventually traced the Cyberium to the villa, but the Cyberman’s power has been drained and so is having difficulty locating the precise location of the Cyberium. The lack of power also means that the Cyberman can not kill anyone in the villa. As The Doctor tries to lure the Cyberman away from the villa, he is struck by lightning, recharging his power core. Rejuvenated the Cyberman prepares to attack the villa again.

The Doctor races to warn the others but instead discovers Percy has been hiding in the cellar, and appears crazed. However, she soon discovers that he has been possessed by the Cyberium, having found it a few days before in the lake, and it has now coursed throughout his body, causing him to write the gibberish - which is actually a future Cybermen language and calculations. The Cyberium was also responsible for creating the supernatural events in the villa so as to prevent its discovery.

The Cyberman then arrives and threatens to kill Percy, to get the Cyberium. The Doctor however, tricks the Cyberium to leave Percy by convincing it that Percy has died. The Doctor then allows the Cyberium to enter her body before the Cyberman can get it. Annoyed at The Doctor's actions the Cyberman then threatens to kill Mary. Realising the impact that this will mean on history The Doctor reluctantly turns the Cyberium over to the Cyberman - despite Captain Jack Harkness's warning. Having got what he wanted the Cyberman then leaves.

The Doctor and her companions depart, making plans to follow the Cyberman to the future using coordinates from Percy's Cyberman-based writings. After they leave, Mary reveals to the others she was inspired by the Cyberman's appearance, ‘This modern Prometheus’, and plans to write a story based on their experience.