Believing the Abbot of Amboise to be the Doctor in disguise, Steven is horrified when the Abbot is murdered!

Hepesh, supported by the delegate from Arcturus, is revealed to be behind the attacks. Arcturus is killed but Hepesh escapes to rouse a rebellion against the King.

As Taren Capel reveals himself and his army of killer robots close in, the Doctor and Leela join forces with the surviving crew members to defend themselves.

Caroline Chikezie is a British actress, best known for playing Sasha Williams in As If, and Elaine Hardy in Footballers' Wives 

Chikezie was born in England to Nigerian parents. At fourteen, Chikezie was sent to boarding school in Nigeria in an attempt to make her abandon her dreams to become an actress. Prior to this she had attended weekend classes at Italia Conti. On her return to the United Kingdom she enrolled into Brunel University where she studied Medicinal Chemistry (she was expected to take over her father's hospital in Nigeria), but left after lecturers decided that she was unsuited to academic life. She later won a scholarship to the Academy of Live and Recorded Arts. 

After roles in Holby City, Casualty, and the award-winning British film Babymother, Chikezie landed her first major role as bitchy Sasha Williams in As If in 2001. In 2004 she played a regular role as Kyle Pascoe's girlfriend Elaine Hardy in Series Four of Footballer's Wives. Other television work includes 40, Judas Kiss, Free Fall and Brothers and Sisters.

She appeared as Lisa Hallett, a member of the secret organisation of Torchwood who had been transformed into a half-human half-Cyberman in "Cyberwoman", an episode of Torchwood, and as Tamara, a fellow demon hunter, in the 3rd season premiere ofSupernatural.

As a film actress, Chikezie has starred as Nasuada in the movie Eragon

Leslie Ash is an English actress.

She is best known for her role as Deborah Burton in the BBC sitcom Men Behaving Badly, Vanessa Lytton in the BBC medical drama Holby City from 2009 to 2010 and Karen Buckley in the ITV drama Where the Heart Is from 2000 to 2003.

Her book My Life Behaving Badly: The Autobiography was published in 2007.

Helen Fielding is an award-winning writer, best known for the Bridget Jones series of books and films.

Before becoming a full-time writer she worked as a researcher and production manager on a number of television shows, including documentaries for the first two Comic Relief charity fundraisers.

John Acheson  was a British actor whose screen career extended from 1970 to 1976.

John Acheson appeared on TV and in the 1970 film You Can't Win 'Em All. He is known for playing Major Beresford in the 1976 Doctor Who story, "The Seeds of Doom".

Brenda Bruce was a British actress. She had a long and successful career in the theatre, radio, film and television.

She appeared in the 1987 Doctor Who story Paradise Towers.

She appeared on television in many dramas, and in a chat show Rich and Rich with her husband. She starred as Winnie in the 1962 British premiere of Samuel Beckett's Happy Days, and in 1977 as Lucilla Edith Cavell Teatime in "Murder Most English".

Bruce played P.G. Wodehouse's character Aunt Dahlia in the 1990s production of Jeeves and Wooster with Stephen Fry and Hugh Laurie