DOCTOR WHO IN DETAIL

After the events of the previous Zygon invasion when there were Three Doctors (see The Day Of The Doctor) a peace treaty was negotiated between humans and Zygons. The treaty resulted in Operation Double, a covert operation to resettle and house 20 million Zygons on Earth, disguised as humans. Most of them in the UK. Working for UNIT are two Osgoods - one human and one Zygon. The Doctor has entrusted them with the Osgood Box, a final sanction if ever the peace treaty should break down. The Osgoods left behind a video about the box in case something should go wrong - such as the death of one of them (see Dark Water / Death In Heaven).

After the death of her sister the remaining Osgood when mad with grief and left for the United States. In the town of Truth or Consequences, New Mexico, Osgood is trying to evade rebel Zygons. She manages to send a distress message to the Doctor before she is caught.

In Brockewll Park, London, the Doctor is trying to be discrete whilst tracking Zygons. He is spotted by two schoolgirls, and the Doctor talks to then about the ceasefire that they should be controlling. When the Doctor is distracted by a call from UNIT two Zygons from a different faction kidnap the two schoolgirls.

Elsewhere Clara, returning home, finds a small boy who says he can't find his parents. In Sandeep's flat she finds the Dad, and tells him Sandeep is looking for him. The Mum comes in, and Clara can see Sandeep being carried, screaming, into another room. When Clara asks about Sandeep the mother says he is fine, and a Zygon attacks Clara.

Since arriving on Earth the Doctor has been trying to call Clara. She she finally returns his call the Doctor, Clara and UNIT go to Drakeman Junior School in Dulwich, London where the Zygon High Command has a secret base. Whilst there UNIT receives another video showing the two schoolgirls - Jemima and Claudette - transforming back into Zygons before being killed by the rebel faction. The Doctor wants to open negotiations with the rebels, but Kate would rather bomb the base in Turmezistan. Instead the Doctor tells Kate to go to Truth or Consequences whilst he goes to Turmezistan, leaving Jac and Clara look after the UK.

At the UNIT command base in Turmezistan the Doctor tries to convince Colonel Walsh not to bomb the Zygons. She is determined and orders the strike. When the drone operator, Lisa, sees a man and a child  waving she aborts the strike. With the strike aborted the Doctor goes with UNIT into the Zygon training camp with 30 minutes before another air strike will hit. Whilst the Doctor and Walsh go round the back of a church Hitchley leads a team to the front. People appear, and one of them is Hitchley's mom. Hitchley's mom claims she is not an imposter, and persuades the team to go into the church to look at proof where they are killed. Inside the church the Doctor finds an underground room where Osgood is being held prisoner and manages to free her before the air strike hits.

In Truth or Consequences Kate finds a practically deserted town. The only person she finds is a Police Officer Norlander. Norlander tells Kate how, two years earlier, Brits had arrived. They had no money, and no jobs, and started fights. Then when one changed into a monster the local panicked, and were killed. When Norlander establishes that Kate has not brought backup she transforms into a Zygon.

With the Doctor and Kate away Clara and Jac goes back to Clara's flat to fetch some things. There they see Sandeep's parents carrying a screaming sack into a lift. The lift seems slower than usual and they race the lift to the bottom floor but it's empty. Inside them notice a goo coming out of the controls. When Clara touches the controls the lift goes to an underground level. At the safe house Jac finds more strange lift occurrences across London. Jac and Clara go back to the underground lift with a UNIT team where they Zygon equipment and pods. One of them contains Clara.

Clara is very keen to destroy the pods, telling Jac they contain Zygon copies. When Jac works out that the pods actually contain the humans that have been copied she realises Clara is actually a Zygon (copied when she first went into Sandeep's flat). With her cover blown Clara orders Zygons to attack Jac and the UNIT troops. Still in human form Zygon Clara later fires a rocket launcher at the Doctor's plane as it returns from Turmezistan.

In her pod the real Clara is awake, and imagines herself inside her flat. Through her TV she can influence the Zygon Clara (Bonnie), and makes the first of Bonnie's rocket miss the place. A second one destroys the plane. Pausing the TV Clara sees two people parachute from the exploding plane. Still influencing Bonnie Clara is able to send a text, with Bonnie unconsciously doing the texting, a message to the Doctor.

At the UNIT safe house Bonnie, using Clara's memories, is able to get a laptop with Osgoods' message about the Osgood box. There she receives a call from the Doctor and Clara, through a series of winks, is able to confirm she is in London. When the Doctor mentions to Bonnie that Clara knows the location of the Osgood box Bonnie returns to Clara's pod, and learns that the Osgood box is located in the Black Archive under the Tower of London.

Bonnie goes to the Black Archive and takes Clara's pod with her. There Bonnie finds two Osgood boxes. She releases Clara and threatens to kill her if the Doctor does not help her choose the correct box. When the Doctor, Kate, and Osgood, arrive at the Black Archive both Kate and Bonnie ask the Doctor which button they should press. Each box has a Truth and a Consequences button. Bonnie wants to free all the Zygons and Kate wants to kill them.

Bonnie tells the Doctor that she wants war. The Doctor desperately pleas with her to think about the consequences. What will happen after the war? What happens, after the war and everything is perfect, to the troublemakers such as Bonnie? The Doctor tells Bonnie about the war he fought in, and the choice he had to make when choosing to press a button to end everything. Eventually the Doctor is able to convince Bonnie to back down, and the ceasefire is restored.

The Doctor offers Osgood a place in the TARDIS. Even though Osgood is a big fan she opts to stay behind and guard the Osgood boxes. Both her and her new *sister*. Bonnie, rather than continue to use Clara's face and body, takes the place of the Osgood that had been killed by Missy.