Doctor Who: The Deadly Assassin

The Doctor (Tom Baker) has finally come home to Gallifrey. But not by choice. Summoned by a vision from the Matrix, he is drawn into a web of political intrigue and assassination. Soon, he will square off against his oldest and deadliest enemy. Plentiful extras. Digitally remastered picture and sound quality.

The Doctor arrives on Gallifrey, where he is accused of the assassination of the Time Lord President. Investigating with the aid of Co-ordinator Engin and Castellan Spandrell, he discovers that this is part of a plot hatched by his old adversary the Master.
Having used up all twelve of his regenerations, the Master is now a wizened husk. He is seeking to control the presidency in order to obtain the official regalia, the Sash and Rod of Rassilon, which are really keys to the Eye of Harmony, the source of all the Time Lords' power.
The Doctor links his mind to the Amplified Panatropic Computer Net, containing the accumulated wisdom of the Time Lords, in the hope of tracking the Master down. In the virtual reality of the Matrix, he finds himself in a life-or-death struggle with a hooded opponent. The Doctor proves the stronger and his opponent is revealed as Chancellor Goth, the leading presidential candidate, whom the Master has been using as a puppet. Following his defeat, Goth dies.
The Master meanwhile seizes the Sash and Rod of Rassilon and starts to access the Eye of Harmony, located beneath the floor of the Panopticon meeting hall, in the hope of drawing off enough energy to enable himself to regenerate. The Doctor manages to stop him before Gallifrey is destroyed, and the Master falls down one of the fissures that have opened up in the floor.
The Doctor then departs in the TARDIS, unaware that the Master has survived his fall and escaped to fight another day.

Directed by David Maloney
Costumes by James Acheson, Joan Ellacott
Film Editing by by Ian McKendrick
Incidental Music by Dudley Simpson
Produced by Philip Hinchcliffe
Script Editing by Robert Holmes
Title Music by Ron Grainer and the BBC Radiophonic Workshop, arranged by Delia Derbyshire
Written by Robert Holmes

Chancellor Goth is excellently portrayed by Bernard Horsfall, who had previously played a Time Lord in season six's The War Games as well as Gulliver in the same season's The Mind Robber and the Thal Taron in season ten's Planet of the Daleks - all three directed, like The Deadly Assassin, by David Maloney.

The Prydonian seal seen in this story (referred to later in the series' history as the seal of Rassilon) had previously appeared as the Vogans' emblem in season twelve's Revenge of the Cybermen - a consequence of both stories having the same designer, Roger Murray-Leach.