Discovering that his old friend, Padmasambhava, is still alive after three hundred years, the Doctor goes to confront him. The Great Intelligence prepares to make its final move.

The Doctor and her friends get back to Yorkshire, meeting Yaz's family, only to find something strange going on with the spiders in Sheffield.

Matt Smith  is best known for his role as the eleventh incarnation of the Doctor

Smith was born and brought up in Northampton where he attended Northampton School for Boys, a state comprehensive secondary school. He had planned to be a professional football player, having played for the youth teams of Northampton Town F.C., Nottingham Forest F.C. and Leicester City F.C. 

After a serious back injury, his drama teacher introduced him to acting by surreptitiously signing him up as the tenth juror in an adaptation of Twelve Angry Men. Although he took part in the play, he declined going to a drama festival that his teacher had signed him up for. His drama teacher persisted, and eventually persuaded him to join the National Youth Theatre in London.

His first theatre roles as part of the National Youth Theatre were Thomas Becket in Murder in the Cathedral and Basoon in The Master and Margarita. His role in the latter earned him an agent and his first professional jobs: Fresh Kills and On the Shore of the Wide World. 

During his tenure in On the Shore of the Wide World, the play transferred to the Royal National Theatre in London. After finishing the play, he took on the role of Lockwood, a pupil in the Alan Bennett play The History Boys. After The History Boys, he would act in the teen play Burn/Chatroom/Citizenship and Swimming with Sharks; the latter being his West End d�but, with Christian Slater. 

His first television role was as Jim Taylor in the BBC adaptations of the Sally Lockhart quartet books The Ruby in the Smoke and The Shadow in the North, opposite {p{73}} in the lead role; he acted with Piper a third time in an episode of Secret Diary of a Call Girl. His first major television role came in the television series Party Animals, a BBC television drama series about fictional parliamentary advisors and researchers in Westminster.

In 2007, Smith appeared as Henry in the critically acclaimed Polly Stenham play That Face at the Royal Court Theatre Upstairs in Chelsea with Lindsay Duncan as Henry's alcoholic mother, Martha, and Felicity Jones�later Hannah Murray�as Henry's drug-addicted sister, Mia. The play transferred to the Duke of York's Theatre in the West End in 2008 and became Smith's second role there. That Face focuses primarily upon alcohol and drug addiction in an upper-middle-class family after the paternal figure in the family leaves.

Smith was one of the earliest actors to audition for the role of the Eleventh Doctor, performing on the first day. The production team, consisting of the incoming producer, Steven Moffat, and BBC Wales Head of Drama and executive producer, Piers Wenger, immediately singled him out based on his performance. 

Smith additionally auditioned for the role of John Watson in the Moffat-created Sherlock, undergoing auditions at the same time; he was unsuccessful, as Moffat believed his eccentric acting style was closer to Holmes, whose role had already been given to Benedict Cumberbatch. 

At 26 years old, Smith was three years younger than Peter Davison was at the time of his casting as the Doctor in 1981, and younger than any other actor suggested for the role. After three weeks of auditions, Moffat and Wenger agreed that it had "always been Matt" and approached him to accept the role. The BBC were cautious about casting him because they felt that a 26-year-old could not play the Doctor adequately; Wenger shared the same sentiment but thought Smith had proven his acting quality in Party Animals, which Wenger thought highlighted Smith's "mercurial qualities". 

 For his performance in his first series he was nominated in the Outstanding Drama Performance Category of the National Television Awards.

Jeffrey Stewart  is a Scottish actor, probably best known as PC Reg Hollis in the ITV drama The Bill, a role he played from 1984 to 2008.

In 2009, Stewart shot a film in Chester, New York portraying a German-Russian in a Soviet prison in Under Jakob's Ladder alongside Australian actor Christopher Elliott, and produced by Roberto Munoz. He won best actor at the 2011 Manhattan Film Festival for the role.^[3] He also voiced Mr. Tickle in The Mr. Men Show.

Stewart has played numerous roles in other television series, including Harry Fellows in Crossroads in 1981 (his first television appearance) and Dukkha in the Doctor Who story Kinda in 1982. He played a police constable in Hi-De-Hi! in 1983, the same year "Woodentop" (the pilot episode of "The Bill"), aired.

Reg Hollis is mentioned but not seen in "Woodentop", so Stewart's first appearance in the series was in the first regular episode, "Funny Ol' Business - Cops & Robbers". By March 2007 Stewart was the last member of the cast remaining from that first episode.

In 2009, Stewart appeared in the video for "Black and Blue" by Swedish band Miike Snow. The video, directed by Vince Haycock, was shot on location in Hackney, London, and featured Stewart as a recluse musician with a penchant for creating animatronic performers in his dingy apartment, and presented the long hair and a large beard he had grown in the year since he left The Bill.

Stewart was born in Aberdeen but moved with his family to Southampton, Hampshire when he was three months old. His father initially worked in the shipyards and then for Fawley oil refinery.

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

Ian Marter played Harry Sullivan appearing alongside fourth Doctor Tom Baker, from December 1974 to September 1975.

After graduating from Oxford University in 1969, Marter initially worked at the Bristol Old Vic theatre, where he was a stage manager as well as acting in various minor roles. In 1971 he auditioned for the regular role of Captain Mike Yates in the eighth season of Doctor Who, and although he did not win the part, he sufficiently impressed the production team to be kept in mind and cast in a supporting role in the 1973 story Carnival of Monsters.

The following year, he was cast in the role of Harry Sullivan, a character developed by the production team when they planned that the incoming Fourth Doctor would be portrayed by an older actor, and thus would not be able to handle the more physical action scenes. 

Marter remained involved with Doctor Who after his departure from the cast. With Tom Baker he co-wrote the script for a potential feature film version, provisionally titled Doctor Who Meets Scratchman, also known as Doctor Who and the Big Game, although this never came to fruition. 

He later became involved with the writing of novelisations of Doctor Who television stories for Target Books, penning nine adaptations in the late 1970s and early 1980s. 

He also wrote an original spin-off novel for Target, Harry Sullivan's War, starring the character he had played on screen, which was published in 1985

Outside of Doctor Who, Marter's acting career consisted mainly of guest roles in episodes of series such as the BBC's Bergerac (in 1981) and Granada Television's The Return of Sherlock Holmes (in 1986). He also had minor roles in several films, such as The Abominable Dr. Phibes (1971) and The Medusa Touch (1978). He lived and worked in New Zealand in the early 1980s, appearing in the New Zealand soap opera Close to Home from 1982.

Ian Marter  died suddenly at his home in London on his forty-second birthday in 1986, after suffering a heart attack brought on by complications of diabetes.

John Hallam was a Northern Irish character actor.

He appeared in many film and television roles including Nicholas and Alexandra (1971), Murphy's War (1971), The Pallisers (1974), The Mallens (1979), Flash Gordon (1980), Dragonslayer (1981), the BBC television adaptations of Prince Caspian and The Voyage of the Dawn Treader (1989) and Robin Hood: Prince of Thieves (1991). He also appears in the director's cut of the 1973 film The Wicker Man as McTaggart.

In 1973 he played the troubled Dr. Peter Conway in the science fiction series Moonbase 3.

He appeared in  Doctor Who as the memorable alien "Light" in the serial Ghost Light (1989). He was also known as Barnsey, the prison cell mate of Den Watts in EastEnders.

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

Actor who had small roles in two Hartnell Stories.

Edmund Bailey was a British actor active from the 1960's and 1970's

He had parts in Dr Finley's Casebook, The Wednesday Play and Z Cars.

Presenter of Blue Peter from 1978-1980

Later became an award-winning war correspondent 

Ian Marter played Harry Sullivan appearing alongside fourth Doctor Tom Baker, from December 1974 to September 1975.

After graduating from Oxford University in 1969, Marter initially worked at the Bristol Old Vic theatre, where he was a stage manager as well as acting in various minor roles. In 1971 he auditioned for the regular role of Captain Mike Yates in the eighth season of Doctor Who, and although he did not win the part, he sufficiently impressed the production team to be kept in mind and cast in a supporting role in the 1973 story Carnival of Monsters.

The following year, he was cast in the role of Harry Sullivan, a character developed by the production team when they planned that the incoming Fourth Doctor would be portrayed by an older actor, and thus would not be able to handle the more physical action scenes. 

Marter remained involved with Doctor Who after his departure from the cast. With Tom Baker he co-wrote the script for a potential feature film version, provisionally titled Doctor Who Meets Scratchman, also known as Doctor Who and the Big Game, although this never came to fruition. 

He later became involved with the writing of novelisations of Doctor Who television stories for Target Books, penning nine adaptations in the late 1970s and early 1980s. 

He also wrote an original spin-off novel for Target, Harry Sullivan's War, starring the character he had played on screen, which was published in 1985

Outside of Doctor Who, Marter's acting career consisted mainly of guest roles in episodes of series such as the BBC's Bergerac (in 1981) and Granada Television's The Return of Sherlock Holmes (in 1986). He also had minor roles in several films, such as The Abominable Dr. Phibes (1971) and The Medusa Touch (1978). He lived and worked in New Zealand in the early 1980s, appearing in the New Zealand soap opera Close to Home from 1982.

Ian Marter  died suddenly at his home in London on his forty-second birthday in 1986, after suffering a heart attack brought on by complications of diabetes.