DOCTOR WHO IN DETAIL

Perivale, London: A man, Dave, washing his car disappears in a flash of light moments before the TARDIS materialises on the side of the street. The Doctor has brought Ace back home. It's not bad enough that the Doctor has brought her back to the boredom capital of the universe, it's also a Sunday when you can't even get a good television programme.

Ace had told the Doctor that she wondered what her old gang were up to, but in Perivale they are not easy to find. Ace takes the Doctor to a hill where the gang used to meet, but it is empty. There's no sign of any people, but there are horses' hoof prints in the ground - even though there are no horses in Perivale.

Ace decides to try the local youth club where they find some people attending a self-defence class run by Sergeant Paterson. The Doctor is not keen on Paterson's use of violence, and leaves him and Ace talking whilst he looks round the clubs. He notices that there seems the theme of "cats" seems to be appearing a lot, and there seem to be a number of stray cats in the area.

The Doctor overhears Paterson and Ace talking. Paterson remembers Ace, and the fact that the police let her off with a warning. He tells Ace that after disappearing she should have at least called her mum., He also says that there have been at least 4 other missing teenagers in recent days.

Trying the high street Ace realises she should have tried the pub first. While she goes inside the Doctor goes into a local shop to buy cat food. He asks the shopkeepers which brand they recommend. Harvey says his cat prefers cheese.  After a cat startles them in the ship the Doctor absent-mindedly walks out without paying, although Ace has won some money of fruit machines in the pub.

Outside a shop one of Ace's friend, Ange, is surprised to see her. The local rumour was that Ace was either dead or had gone to Birmingham. Ange tells Ace that most of her friends have gone, but she doesn't know when. The first two, Steve and Midge, disappeared a month earlier, but Shreela had disappeared the previous week.

Stuart, who had been in Paterson's self-defence class, on a run, is observed by a cat and moments later disappears in a flash of light.

On a side street, whilst Ace is reminiscing about her time in Perivale the Doctor starts opening up his cat foot and scooping it onto the pavement. He hides in a garden to watch. Ace leaves the Doctor to his cat watching and goes to a play area where she sees a stray cat. As the cat jumps down Ace feels a wind behind her, and sees a Cheetah on horseback. She manages to get under a climbing frame where the horse cannot get to her and calls for the Doctor, who abandons his cat watching after a dog was attracted by the food. She tries to make a run for it but she, the Cheetah and the horse disappear moments before the Doctor arrives.

Ace finds herself transported to an alien world. In the distance there are explosions, and close by is the dead body of Dave, and a couple of cats. A few minutes later the Cheetah on horseback appears and continues the chase. Ace slips in the sandy path she is on, and the Cheetah dismounts. Stuart tries shouting at the Cheetah to distract it, and it goes after him and kills him. It then remounts the horse and takes his body away, leaving Ace behind.

A few moments later Ace sees Shreela emerge from a wooded area. Further in they find Midge and Derek. When Ace asks about Steevie Midge says he is cat food.

On Earth the Doctor is trying to capture a cat. Each time he tries he is caught by Paterson who is patrolling the area as part of his neighbourhood watch duties. When trying to sneak up on one cat Paterson grabs the Doctor, startling the cat. When it jumps down from a wall the Doctor and Paterson are transported to the alien world, and into a camp of Cheetahs. The Cheetahs direct the Doctor towards a particular tent where he finds a familiar face... the Master.

The Master throws a ball towards Paterson and the Cheetahs start playing with him whilst the Master takes the Doctor to one side to talk to him. Instead the Doctor escapes on a horse, rescuing Paterson. As they leave the Master tells the Doctor he is in control of the Cheetahs.

As they are riding the Doctor tells Paterson they are on the planet of the Cheetah people. Paterson, who always thought he was ready for anything, admits he was not prepared for another planet. They do eventually find Ace after riding into one of her tripwires and getting caught in a trap.

The Doctor realises the planet is breaking up, and he and Paterson lead the remaining people across the planet. The Doctor works out where the safest place is and attempts to lead the group towards safe ground. This means going through a group of Cheetah people very slowly so they are not alarmed.  But when a man appears at the top of a hill yelling in terror and runs through the group of people they start to fight back. The Doctor tries to get them to stay still, but even Ace tries to help. She manages to knock one Cheetah person off its horse with a rock, and after a few nmiutes the Doctor is left alone.

Ace makes her way to a small lake. She sees the Cheetah person she knocked off collapse into the water and immediately runs round it to help. When it recovers a links is established between the Cheetah person and Ace. It is able to ask Ace for water, which she fetches.

Elsewhere Midge is chased by a Cheetah person. A second Cheetah person fights the first, and when one runs away Midge is able to kill the other one.

Looking for Ace the Doctor finds his way to some old ruins where the Master is waiting for him. When more explosions are heard the Master tells the Doctor that the planet is alive and the Cheetah people are part of the planet. When they fight they trigger explosions, hastening the planet's destruction. The Master also tells the Doctor that he needs his help. The Cheetah People are only able to bring people to the planet, and he needs the Doctor to find a way off the planet.

The Doctor finds Ace and the Cheetah person. The Doctor knows he needs to find an animal whose home is Earth, and encourages Ace to become friends with the Cheetah person. The Master overhears the conversation about how to get away from the planet.

Paterson, Shreela and Derek manage to escape, and are rejoined by Midge. When Paterson starts trying to motivate the group Midge attacks Derek. Hearing cries the Doctor and Ace rush to help, and the Doctor realises that after killing one of them Midge has made a connection to the Cheetah people. When Midge starts to run the Doctor and the rest of the group follow.

The Master finds Midge first, and holding onto him tells Midge to "go home". In a flash both Midge and the Master disappear. When the rescued Cheetah person appears Ace's eyes show she also has a connection with them.

When Ace and the Cheetah person - Karra - run off together the Doctor follows. He finds Ace just before she is going to shared an animal that been killed with Karra. Taking her back to Paterson, Shreela and Derek the Doctor tells Ace she has the power of the Cheetah people, but that if she does take her prey home she could become like them forever. Ace makes her choice, and holding hands they all return to Earth.

Back on Earth Shreela and Derek are thankful but Paterson can't accept what happened and thinks he suffered a blackout in the road. Ace, back to normal, wants to leave, but the Doctor is concerned about the Master.

Nearby the Master struggles to free himself of the Cheetah people's planet's control, whilst Midge succumbs further to its influence. Whilst the Master, and an even more confident Midge, go back into town the Doctor and Ace arrive at Midge's flat. They find a dead cat and a crying girl, Midge's sister Squeak.  She tells the Doctor that the bad cat, meaning Master, killed it. Ace is not quite free of the Cheetah people, and is able to track the Master to the youth club.

In the youth club a group is waiting for Paterson's self-defence class. Midge, with power from the Master and the Cheetah people, is able to hypnotise the group into following his orders. When the Doctor and Ace arrive at the club they find Paterson's body, but no sign of Midge or the Master. Ace is able to track the Master to the hill where at the bottom the Doctor and Ace find a motorcycle.

At the top of the hill Midge is on another motorcycle flanked by people from the youth club - and the Master. Ace is prepared to play the game of chicken, but the Doctor pulls her off the bike saying if she fights she will change forever. Instead he gets on the bike and drives towards Midge, and both bikes collide.

Midge is thrown clear, but the Master tells him he has failed, and using his powers commits suicide. With Midge gone the group of people advance towards Ace. Resisting the urge to fight she calls for help, and Karra appears and causes the group to run. When Karra confronts the Master he kills her. As she dies Karra transforms back into the human she used to be.

The Doctor is also throw clear, and ends up on an old sofa. Returning to the TARDIS he finds the Master trying to pick the lock. The Master says with his new power he can destroy the Doctor, and transports them both back to the Cheetah people's planet. As the Master attacks the Doctor the Doctor is able to transport home - to just outside the TARDIS.