DOCTOR WHO IN DETAIL

Still blind from the previous adventure aboard the Chasm Forge (See Oxygen) the Doctor is down by a vault, remembering events that happened a long time ago.

It is very difficult to kill every species. Every species is different and a different method is required. One planet specialises in being able to execute any species - and that includes Time Lord. The Doctor is being taken to the execution of a Time Lord. The Doctor is told how the execution will take place, and that after termination the body is held in a Quantum Fold chamber under guard for at least 1,000 years. Another stipulation is that another Time Lord must perform the execution.

Which is why the Doctor is there: to perform the execution of Missy. The Doctor promises to look after her body for a thousand years. But the agreement did not specify dead.

In the present the Doctor is interuppted by a simple message: Extremis. 

In an empty lecture theatre, with the lights dimmed, the sonic glasses deteect a number of people entering the room. Nardole appears in time to help describe what is happening. A Cardinal tells the Doctor that the Pope requests a personal audience. A few moments later the Pope appears. The Pope doesn't go around making personal visits, and when the Doctor asks why the Pope says one word: Extremis.

The Doctor takes the Cardinal and the Pope back to his office in the University. The Cardinal explains to the Doctor that there is a document that no-one can translate. An early Christian sect managed to translate the document, but one one word survives: Veritas (The Truth). All copies of the translations were destroyed, and the sect committed mass suicide, and the translation died with them. After many months of work the Veritas was translated, but all copies were destroyed and anyone who worked on it killed themselves.

Even though everyone who has read the Veritas has been compelled to kill themselves the Pope asks the Doctor to read the Veritas.

At her home Bill has brought a date back - Penny. Things seem to be going okay, until the Pope appears. Penny sees the Pope, a group of priests, and the TARDIS, and makes a quick exit. Bill, understandably, is not happy. At the Cardinal's request the Doctor takes to the TARDIS to a huge library that few people know exists: the Haereticum.

At the centre is a strange light. Throught the sonic glasses the Doctor senses a door, but the Cardinal says there is no door. When the Cardinal goes to investigate the light disapppears. The Cardinal remains to check the wall for a breach whilst the Doctor, Bill, and Nardole, go to a cage that contains Vertias. The cage should be a lock, but a priest has broken in. The priest, scared, runs off. 0The cage contains a laptop, and a reading chair with restraints. Examining the laptop it looks as though the priest emailed a copy of the Veritas translation to the CERN laboratory. 

After hearing a gunshot (the priest) the Doctor asks Nardole and Bill to investigate. He tells Bill that he won't try to read the Veritas (and Nardole believes him as he is still blind). They find the dead priest, and also the strange ligh. Going through the light they find a white room with numerous other portals. One leads to the the Pentagon, another back to the Vatican. Another takes them to CERN. At CERN there is a party where everyone is getting drunk before a mass suicide after reading the Veritas. Nardole and Bill only just make it back to the portal room before CERN explodes. In the portal room it dawns on Nardole that they aren't just portals to other areas, they are projections. The room is actually projecting - and not just transporting to - different simulations of the world. Nardole tests an idea and put his hand outside a projection - and disappears.

Back at the Haereticum the Doctor has taken a device from the TARDIS that is able to borrow energy from the future allowing him to temporarily regenerate his eyes so he can read the Veritas. Not sure what will happen the Doctor asks the Cardinal help restrain him in the chair. Instead some other monks, looking like dead people, appear. They take the Veritas, but the Doctor escapes with his device, and the laptop.

In the portal room Bill follows a blood trail and appears in the Oval Office in the White House. There she finds the President, who has committed suicide. The Doctor is sitting at the President's desk. The President had read the Veritas, and the Doctor has listened to it. The Doctor tells Bill that the Veritas speaks of a demon who wants to conquer the world. In order to do that he creates a Shadow world in which to practice - complete with simulated peopele. In some cases the simulated people can learn they are simulated, and they might rebel. All the people who committed suicide they were in fact escaping.
As they talk Bill starts to disappear. Behind her is a Monk. The Doctor asks the Monk to delete him, but the Monk says he has been killed many times for them to gain information. 

The Doctor tells the Monk that the simulation is too real. He tells the Monk that his sonic glasses have been recording everything from the last few hours, and that he has the ability to email the recording. He does what everyone does when they are in danger - call the Doctor. He sends the message to the real Doctor - with the subject: Extremis.