DOCTOR WHO IN DETAIL

After the events of The Legend of Ruby Sunday at the convention centre Sue Triad, under the control of Sutekh, uses Sutekh's power to turn people who have not escaped to dust. In UNIT HQ Harriet Arbinger uses Sutekh's power to reduce the UNIT personnel, including the Vlinx, to dust. The Doctor and Mel return to UNIT and find Ruby safe inside the time window, unaware of the chaos in London caused by Sutekh reducing people to dust. The Doctor runs into the TARDIS inside the time window. It's not his TARDIS, and is smaller on the inside, but a remembered TARDIS, powered by Ruby's memories, and filled with memories from the Doctor's travels.

Inside the time window Sutekh appears around the Doctor's real TARDIS, piloted by Harriet. Sutekh tells the Doctor after he was cast into the time vortex (see Pyramids of Mars) he clung to the TARDIS and hid. Sutekh also saw many secrets and was able to use the name Susan as trap for the Doctor. Wondering why he is still alive, given Sutekh has had plenty of time, the Doctor, Ruby, and Mel, squeeze into the remembered TARDIS. It's a rough ride, with the TARDIS catching fire, until the Doctor manages to calm things down using intelligent rope (similar to the intelligent gloves) and stabilise the TARDIS. Once stabilised the Doctor opens the doors and they can see the dust of death spreading all over the world - killing all life on the planet.

Everywhere the TARDIS landed Sutekh created a manifestation of Susan Triad leaving a presence everywhere, and now spreading Sutekh's gift of dust to other worlds including the Odd Sphere and even the home of the Daleks - Skaro. But there is one person who manages to live - and the person is linked Ruby.

On a now dead planet the Doctor finds a survivor, alone, with a baby. The woman memories are dying and cannot remember who she is, or the name of the planet. The Doctor asks for some metal, and is given a spoon before the woman also turns to dust.

Using metal from the spoon the Doctor is able to activate the screen. The screen is still linked tot the time window, and Ruby's memories. When Ruby mentions her mother the screen reacts, and the Doctor realises Ruby's mother is the one thing beyond Sutekh's comprehension - the one person he can't see. As Ruby holds the screen it gives a hint: 2046 DNA testing became compulsory for all people - which would include Ruby's mother.

As the TARDIS travels to 2046 Mel begins to feel Sutekh in her mind. In the Department of Health in 2046, now devoid of life, the Doctor is able to take a sample of Ruby's DNA and, use the database to find the identity of Ruby's mother. As it starts to snow a match is found - and Mel falls fully under Sutekh's control. The Doctor, Ruby, and Mel, are transported back to UNIT in 2024.

Sutekh demands the name of Ruby's mother, and when Sutekh threatens the Doctor Ruby offers the screen with the details to Sutekh - before dropping it on the floor where it smashes. Once she is close to Sutekh Ruby hooks the intelligent rope from the TARDIS to a collar on Sutekh. Both wearing an intelligent glove both Ruby and the Doctor hold onto the rope. They separate Sutekh from the proper TARDIS, and they both rush inside. The Doctor hooks the rope to the TARDIS console and as the TARDIS dematerialises so does Sutekh.

The TARDIS flies into the time vortex dragging Sutekh along. As the TARDIS goes through time Sutekh's dust is reversed and life returns to Earth, and other worlds. The Doctor closes the TARDIS doors cutting the rope and leaving Sutekh in the time vortex.

With everyone restored UNIT finds Ruby's real mother - Louise Alison Miller - as well as the name of her father - William Benjamin Garnet. There is nothing special about Louise, but because she was important to Ruby, and then by other people, this made her existence more powerful than Time Lords and gods.

After finally meeting, and getting to know, her mother Ruby chooses to leave the Doctor and stay behind and look for her real father.