The Doctor and his friends have been given shelter from the Daleks by the Aridians. But the Daleks threaten to kill the Aridians unless they hand over the time travellers.

Devil's End is sealed off from the outside world by a heat barrier. The Doctor and Jo return to the barrow where they are confronted by the gargoyle, Bok.

Gregg Sulkin is an English actor. At age ten he made his film debut in the 2002 Doctor Zhivago mini-series. He later landed the starring role in the 2006 British release Sixty Six, and subsequently became known for appearing in the Disney Channel comedy series As the Bell Rings and Wizards of Waverly Place. In 2010, he starred in the Disney Channel television movie Avalon High. He also appears in the television special The Wizards Return: Alex vs. Alex. He is currently a main character on the MTV's show Faking It.

Sulkin was born in London. He is Jewish and had his Bar Mitzvah by the Western Wall in Jerusalem. He attended Highgate School in North London.

Sulkin made his acting debut in the 2002 mini-series Doctor Zhivago. He subsequently starred in the comedy Sixty Six, as Bernie Rubens, alongside Helena Bonham Carter, Eddie Marsan and Catherine Tate. Sulkin also played the role of JJ in the Disney Channel comedy, As the Bell Rings, worked on a CBBC children sci-fi show The Sarah Jane Adventures (spin-off of Doctor Who), playing Adam in series 3 two-episode story The Mad Woman in the Attic.

Sulkin was on Disney Channel's Pass the Plate as Gregg from the UK. He had a recurring guest role on the Disney Channel series Wizards of Waverly Place, where he played Alex's love interest Mason Greybeck he reprised his role in 4 episodes of season 3 and returned to the series in its fourth season, and through to its finale.

Sulkin has also landed a role in the thriller The Heavy.

In 2010 he went to New Zealand making a Disney Channel film Avalon High, which premiered on 12 November 2010. In an interview with Kyle Martino, aired on Soccer Talk Live on the Fox Soccer Channel in the US, Gregg announced that he was a fan of Arsenal.

Sulkin was on the Disney Channel's Friends for Change Games and was on the Yellow Team.

He reprised his role as Mason Greyback in The Wizards Return : Alex vs. Alex on Friday, 15 March on Disney Channel.

In 2012, Gregg was starred in the American teen drama series Pretty Little Liars as a recurring character, Wesley Fitzgerald brother of Ezra Fitz.

In February 2013, it was announced that Sulkin would play Julian Fineman in FOX's television adaptation of Lauren Oliver's young adult novel, Delirium. On 8 May, it was reported that Fox has decided not to pick up Delirium.

_{Biography from the wikipedia article, licensed under CC-BY-SA}

Pearl Mackie comes from Brixton in South London. She trained as an actor at Bristol Old Vic Theatre School, graduating in 2010. 

Since drama school she has worked across Theatre, Film, Television and Radio appearing at the RSC, The Park Theatre, The Finborough, for the BBC and on London’s West End. In 2014 she played the guest lead in the BBC television series Doctors episode Love is Blind. She performed in Obama-ology by Aurin Squire at the Finborough Theatre in 2015, and at the time of her casting announcement (23 April 2016) she was appearing in the National Theatre's production of The Curious Incident of the Dog in the Night Time at The Gielgud Theatre.

Brian Treitler played Dr Murphy in Torchwood Dead of Night.

Dursley McLinden was a Manx actor whose career was mostly focused on the London stage in musicals such as The Phantom of the Opera, Gigi, and Follies. 

McLinden was born and grew up in Douglas, Isle of Man, and at the age of eight, at Douglas High School, he played the Dame in Dick Whittington. He came to London when he was 16 to train at the Mountview Theatre School and first toured America and Sweden in productions of The Threepenny Opera and Macbeth. 

Shortly afterwards he won a role in Derek Nimmo's production of The Man Most Likely To . . ., touring the Middle and Far East. His work in repertory included Crucifer of Blood in Ipswich, To Kill a Mocking Bird and Damn Yankees in Birmingham, and Robert and Elizabeth at the Chichester Festival Theatre. He appeared in the West End in Lerner and Loewe's Gigi at the Lyric Theatre, Shaftesbury Avenue, and in Stephen Sondheim's Follies at the Shaftesbury Theatre.  

In 1988 he was diagnosed with AIDS. Over the next seven years he became one of the moving spirits behind West End Cares, the theatrical wing of the Aids charity Crusaid. He was particularly the inspiration behind cabaret nights at Smith's restaurant in Covent Garden 

McLinden, who was also an accomplished conjuror, continued working as an actor up until a few weeks before his death. His last performance was in Andrew Lloyd Webber's The Phantom of the Opera at Her Majesty's, on the night before his 30th birthday.

David Kinder played Billy in the Doctor Who serial Delta and the Bannermen.

Also appeared in The Wounded, The Natural History of Parking Lots, Grange Hill, Killing American Style, Casualty

Oliver Smith  is an English actor. 

He is probably best known for playing the role of Frank the Monster from the original Hellraiser film in 1987, as well as Mr. Browning and Skinless Frank from Hellbound: Hellraiser II film in 1988. In May–June 2010, Smith narrated the commercial for the DVD and Blu-Ray releases of Life.

_{Biography from the Wikipedia article, licensed under CC-BY-SA}

Anita Briem is an Icelandic actress. 

She is known for her role as Jane Seymour on The Tudors and her role as Hannah in Journey to the Center of the Earth.

She played Sally Jacobs in the 2005 Doctor Who story The Christmas Invasion.

Also worked on You, Me & The Circus, Elevator, Queen of Hearts, Everything Will Happen Before You Die, Dylan Dog: Dead of Night, Adventure at the Center of the Earth, ourney to the Center of the Earth, Cold Trail, The Evidence

Neville Jason played Prince Reynart in the 1978 Doctor Who story The Androids of Tara.

Also appeared in Venetica, Anno 1404, Ahead of the Class, Poor Little Rich Girl: The Barbara Hutton Story, The Tripods, Dempsey and Makepeace, Minder, Angels, Skorpion, Goodbye Darling, The Passage, Armchair Thriller, When the Boat Comes In, The Duellists, The Message, Warship, The Dancing Years, Churchill's People, Barlow, The Zoo Gang, The Carnforth Practice, The Dragon's Opponent, BBC Play of the Month, Theatre 625, Mr. Aitch, Dixon of Dock Green, The Troubleshooters, The Amorous Adventures of Moll Flanders, Maigret, From Russia with Love, No Hiding Place, Hamlet, Storyboard, ITV Play of the Week, Fact and Fiction, The Little Ship, The Black Arrow, Sword of Freedom

His theatre credits include: Publius in the play "Titus Andronicus" by William Shakespeare , directed by Peter Brook (Stoll Theatre, London, 1957); various roles in "The Knight of the Burning Pestle" by Francis Beaumont (Aldwych Theatre, London, 1981); John Fryer in the musical "Mutiny!" (London, 1985). 

Frederick Jaeger was a German-born actor who found success working in British television.

Jaeger was born in Berlin, but moved to England following Adolf Hitler's rise to power in Germany. He was educated at Lord Weymouth's Grammar School, Warminster, and the Guildhall School of Music and Drama, from which he graduated in 1948, becoming a British subject two years later. He made his first theatre appearance in 1949, and his film debut, The Black Tent, in 1956. 

He had roles in three Doctor Who stories. He appeared as Jano in The Savages in 1966, and as Professor Sorenson in Planet of Evil in 1975. In 1977's The Invisible Enemy, he appeared as Professor Marius, creator of the robot dog K-9.

Christopher Coll  played Phipps in the 1969 story The Seeds of Death and Stubbs in the 1972 story The Mutants.

He played Mr. Malcolm in the first series of Grange Hill and had roles in Z-Cars and Coronation Street

Australian actor who appeared in the 1975 story The Ark in Space.

He later went on to appear in Home and Away playing Rev. John Newton

Aubrey Richards was a Welsh born actor who appeared in many film and television productions over a 40-year period, often portraying professors.

He started acting in repertory theatre. His films included The Ipcress File (1965), It! (1967), The Man Who Haunted Himself (1970), Under Milk Wood (1972), Endless Night (1972) and Savage Messiah (1972) as the mayor. On television he had a major role as Samuel Evans in Carrie's War (1974) and recurring roles in Emergency-Ward 10, the Doctor Who adventure The Tomb of the Cybermen (1967) as Professor Parry and How Green Was My Valley (1975–76) as Mr. Elias.

He was married to the distinguished stage manager Diana Boddington and they had two children, Claudia and David.

Biography from the wikipedia article, licensed under CC-BY-SA

Ramsay Williams played Congressman Brook in the 1973 story Frontier in Space