Ian and Barbara find a temple in the middle of a hostile jungle. Inside is the ailing Darrius, keeper of one of the keys. As Darrius dies he gives Ian a clue to find the key.

On board a vast spacecraft, the Doctor meets the alien captain who demands the return of the three ambassadors sent to Earth or he will destroy the world.

Jonathan Bailey is an English actor, best known for the ITV drama Broadchurch, the BBC's Leonardo as a young Leonardo da Vinci and the Channel 4 comedy Campus .

Bailey first began working as an actor on the ITV series Bramwell. After playing parts in various television series and films, Bailey secured a small role as sport enthusiast Flatpack in the sitcom Campus. In 2011, he was cast as Leonardo da Vinci in the program Leonardo and went on to play opposite Sarah Alexander in the BBC comedy Me and Mrs. Jones.

He was nominated for the award for Outstanding Newcomer at the Evening Standard Theatre Awards 2012 for his performance in David Hare's South Downs.

Bailey has played the role of Tim Price in the musical American Psycho at London's Almeida Theatre since December 2013.

In September 2014, he played the character Psi in the Doctor Who series 8 episode, "Time Heist".

He portrays small town reporter Olly Stevens in the ITV series Broadchurch.

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

Cyril Nri is a British actor, writer and director. 

He attended the Young Vic Youth Theatre in Waterloo, London. He trained at the Bristol Old Vic Theatre School, and is probably best known for playing the role of Superintendent Adam Okaro, now Chief Superintendent, in the long-running ITV police drama The Bill. He also had a cameo role as Graham, a barrister colleague of Miles and Anna, in several episodes of the cult BBC TV drama series This Life.

Nri attended Holland Park School in West London and appeared in a school production of Three Penny Opera.

In 2008, he starred alongside other former The Bill favourites, Philip Whitchurch and Russell Boulter in an episode of BBC1's Waking the Dead.

In 2009 he appeared in The Observer at the Royal National Theatre.

In 2009 and 2010 he appeared in Law & Order UK as a Judge Demarco.

In February 2010 he guest starred in Doctors.

In November 2010, he appeared in Series 4 of The Sarah Jane Adventures, in the "Lost in Time" episodes. He later reappeared in October 2011, in the Series opener of Series 5, "Sky"

John Ogwen  is a Welsh actor.

He played Bostock in the 1985 story, Revelation of the Daleks. 

Best known to British audiences for his starring role in the 1978 drama series Hawkmoor, and appearances in the television seriesThe District Nurse and the Doctor Who serial Revelation of the Daleks, Ogwen has been a stalwart of Welsh language television and film since the early 1970s. He has also written plays, presented documentary series and recorded readings of Welsh-language works.

In 2004 he was awarded a BAFTA Cymru Special Award for his contribution.

He was born and raised in Sling, Bethesda, North Wales, and studied English and Welsh at Bangor University. When told, "You'll have to make up your mind whether you want to be a nationalist or an actor", he replied, "I'll be a bit of both."

He has a keen interest in football, and played as a striker for Bangor City F.C. when still in the 6th Form at school. Today he is a keen Everton F.C. supporter.

He is married to Maureen Rhys, one of Wales' most recognisable actresses, and in the past they have frequently worked together in productions. They have three children, and live in Bangor.

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

Paul Whitsun-Jones was a Welsh actor.

He appeared in the 1966 Dcotor Who story, The Smugglers and the 1972 story The Mutants.

He was educated at Merchant Taylors' School, Northwood, Middlesex. Whitsun-Jones played the role of Mr Bumble in the original West End production of the musical Oliver!

George Coulouris was a prominent English film and stage actor.

Coulouris was born in Manchester, England,  and was educated at Manchester Grammar School. He attended London's Central School of Speech and Drama, in the company of fellow students Laurence Olivier and Peggy Ashcroft.

Coulouris's stage debut was in 1926 with Henry V at the Old Vic, and by 1929 he made his first Broadway appearance, followed by his first Hollywood film role in 1933.

A major impact on his life was Orson Welles, whom he met in 1936. He joined Welles' Mercury Theatre, and played Mark Antony in their opening modern dress production of Julius Caesar. In Citizen Kane (1941), Coulouris played Walter Parks Thatcher, a financier similar to J. P. Morgan. George Coulouris won a National Board of Review 'Best Actor' award in 1941 for his performance in Citizen Kane. Orson Welles was the only other Citizen Kane actor to win the same award.

During the 1930s and 1940s he remained a regular figure on the stage and screen, starring in his own Broadway production of Richard III in 1943. His films in this period included For Whom the Bell Tolls (1943), Mr. Skeffington (1944) and Watch on the Rhine (1943), for which he received an Oscar nomination. He also gave a notable performance as Robert de Baudricourt, in the Technicolor spectacular, Joan of Arc (1948), starring Ingrid Bergman. 

Coulouris returned to Britain after 1950, and appeared in more films, theatre and television productions. His stage work included the title role in King Lear at the Glasgow Citizens' Theatre (1952); the lead (Dr. Stockmann) in An Enemy of the People (1959) at the Cambridge Arts Theatre; Peter Flynn in Sean O'Casey's The Plough and the Stars at the Mermaid Theatre (1962); a part in August Strindberg's The Dance of Death; and Big Daddy in Tennessee Williams's Cat on a Hot Tin Roof (1970).

Later film roles included parts in the Doctor in the House films, Papillon, the biography of Mahler, The Long Good Friday and Murder on the Orient Express. During his life he played in over eighty films.

Radio roles were also numerous, and his television roles included parts in Danger Man and The Prisoner episode "Checkmate", and an appearance as Arbitan in the Doctor Who serial The Keys of Marinus.

 He died on April 25, 1989, of heart failure following Parkinson's disease in London.