Arriving on the planet Dido, the Doctor, Barbara and Ian discover a crashed spaceship from Earth and survivors. They are terrorised by the monstrous Koquillion who attacks Barbara.

The Master, a renegade Time Lord and a rival of the Doctor's, arrives on Earth and paves the way for an invasion by the insidious Nestene Consciousness.

Catherine Bailey is an English actress.

Catherine Bailey started acting at the age of 12 when she landed the lead role of Helen Green in Uncle Jack, a BBC television series starring Paul Jones and Fenella Fielding. She went on to appear as Ilse in Tim Supple�s acclaimed production of Spring Awakening at the RSC at the age of 15, and her next role was as Gina Wild, the rebellious teenage Goth in the BBC comedy The Wild House, which was nominated for Best Children�s Comedy at the British Comedy Awards.

Notable television appearances since then have included: Holby City, Eastenders, Peak Practice, Rosemary and Thyme, The Bill, My Family, Urban Gothic, 55 Degrees North, Egypt, The English Harem and Residents. She has also worked in Radio, most recently on BBC Radio 3 as Isabella in The Changeling, Directed by Jeremy Mortimer.

On stage she has appeared at the Young Vic (�Tis Pity She�s a Whore), Tricycle Theatre (Walk Hard - Talk Loud), Hackney Empire (in Steven Berkoff�s Sit and Shiver), Theatre Royal Haymarket (The Country Wife) and the Oval House for Paines Plough (House of Agnes). She recently appeared in a televised performance of A Midsummer Night's Dream at Middle Temple Hall, directed by Tim Carroll and featuring The Orchestra of the Age of Enlightenment.

She is an associate member of The Factory Theatre Company, having appeared in many of their productions including Hamlet, The Seagull, Round 1, Round 2 and As You Like It.

She most recently worked on The Sarah Jane Adventures for the BBC, and in House of Anubis for Nickelodeon, as recurring character Esther Robinson. She is currently appearing as Annabella, Margaret and Pamela in The 39 Steps at the Criterion in London.

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

David Gyasi has appeared in a number of shows, including Waking the Dead, Apparitions and Demons, with larger roles in Mike Bassett: Manager, and more recently in White Heat as Victor.

Toby Hadoke is an English actor, writer, and stand-up comedian.

He is particularly well-known for his work on the Manchester comedy circuit, where he performs regularly. He runs the multi-award-winning XS Malarkey comedy club, and is involved with many of the more experimental and financially accessible nights in the region. 

His first one-man show, Moths Ate My Doctor Who Scarf, which charted his passion for Doctor Who in an autobiographical manner, was a critical and popular success at the 2006 Edinburgh Festival Fringe.

A sequel, My Stepson Stole My Sonic Screwdriver, was performed at the 2012 Edinburgh Festival Fringe to similar critical acclaim.

Hadoke can frequently be heard in the BBC DVD range, providing moderation for a number of commentaries and also presenting featurettes. He also voiced the role of Forester (originally played by Alan Tilvern) for The Urge To Live (Reconstruction) - the reconstructed fourth episode of Planet of Giants that was included on the DVD release of the story.

Lucy Davis is an English actress. She is best known for playing the character Dawn Tinsley in the BBC comedy The Office and as Dianne in the horror-comedy movie Shaun of the Dead.

Davis's first role was in a 1993 episode of The Detectives. Davis played Maria Lucas in the BBC's 1995 production of Pride and Prejudice. She has also appeared in the film Sex Lives of the Potato Men (2004), had a role in Shaun of the Dead (2004), and played Hayley Jordan in The Archers on BBC Radio 4. She gave up the latter role when her other acting responsibilities made it impossible to continue; the part was recast in September 2005.

She appeared in the episode Elephants and Hens of UK TV programme Black Books

She was reportedly offered a role in In Her Shoes that eventually went to Toni Collette. In 2006, Davis appeared as the 'Fashion TV' host on ABC's hit Ugly Betty, and later that year played writer Lucy Kenwright in NBC's Studio 60 on the Sunset Strip. In 2008, she appeared in several episodes of the U.S. series Reaper. In 2010 Davis starred in ITV's six-episode comedy drama, Married Single Other, and also appeared in a guest role in The Mentalist alongside her then husband Owain Yeoman. Davis also stars in the John Landis-produced thriller Some Guy Who Kills People. In 2012, Davis had a guest voice part in Family Guy for the episode Be Careful What You Fish For.

Deborah Watling  is a British actress best known for her role as Victoria Waterfield, a companion of the Second Doctor.

Watling was born at Fulmer, Buckinghamshire, the daughter of actors Jack Watling and Patricia Hicks. Her sister Dilys and her brother Giles are also actors. Beginning as a child actress, notably as the niece of Peter Brady in the 1958 series The Invisible Man, she later starred in Alice, Dennis Potter's version of Alice's Adventures in Wonderland, for the BBC's The Wednesday Play strand in 1965, a small role in That'll Be the Day and as Norma Baker in the ITV series Danger UXB in 1979.

Watling played Victoria in Doctor Who from 1967 to 1968, though, only one serial that she played in exists in its entirety, "The Tomb of the Cybermen". She also appeared in Dimensions in Time (1993) and Downtime (1995). Her father, Jack Watling, appeared in Doctor Who as Professor Travers in the serials The Abominable Snowmen and The Web of Fear as well as Downtime. 

She co-starred with Cliff Richard in the 1970s film Take Me High.

Official Website

John Woodnutt was a British actor.

Born in London he made his acting debut at the Oxford Playhouse at the age of 18.

He had many television and film roles, including that of Henry VII in the first episode of The Six Wives of Henry VIII (1970); Sir Watkyn Bassett in the television version of Jeeves and Wooster (1990 to 1993); and Merlin and Mogdred in the children's adventure game programme Knightmare (1987-1990). One of his earliest television roles was in 1956 in the ITV drama One, broadcast live. He appeared five times in Z-Cars and once in Softly, Softly.

He appeared Doctor Who four times, in Spearhead From Space (1970) as Hibbert, Frontier In Space (1973) as the Draconian Emperor, Terror of the Zygons (1975) in the dual roles of Broton and the Duke of Forgill and The Keeper of Traken (1981) as Seron.

He appeared in The Avengers episode "Quick-Quick Slow Death" in 1966 and played "The Spidron" in the cult science fiction series The Tomorrow People in 1973. He also appeared in the Look and Read educational serial "The Boy From Space" in 1971, as the Thin Spaceman; in the 1976 HTV series Children of the Stones as the sinister butler Link.; and in the 1978 series The Doombolt Chase. 

In the 1980s, he played various guest roles in several television movies such as Hitler's S.S.: Portrait in Evil, starring Bill Nighy and John Shea. In the BBC Scotland television series of The Secret Garden, made in 1975, he played the part of Mr. Archibald Craven. He appeared in producer Barry Letts's classic serials Sense and Sensibility, Stalky & Co., and The Pickwick Papers. He played the Senior Tutor in Porterhouse Blue, appeared regularly as Sir Watkyn Bassett in the Jeeves and Wooster series alongside Stephen Fry and Hugh Laurie and also appeared briefly in the comedy sketch show Paul Merton: The Series in the early 1990s.

Radio and television Sherlock Holmes stories in which he appeared included the BBC Radio 4 adaptation of The Hound of the Baskervilles and, as Mr. Merryweather, The Adventures of Sherlock Holmes with Jeremy Brett in the episode entitled "The Red-Headed League". He also made an appearance in the 1965 Douglas Wilmer Sherlock Holmes series on the BBC.

Victor Carin  played Doctor McKenzie on Coronation Street in 1967. 

He appeared in the 1966 Doctor Who story The Gunfighters.

His other credits include  Sutherland's Law and Raffles.