Season 20

Season 20 of Doctor Who ran between 3 January 1983 and 25 November 1983. It starred Peter Davison as the Fifth Doctor.

Overview
The season consisted of six serials and twenty-two episodes of twenty-five minutes each, plus a ninety minute twentieth anniversary special, The Five Doctors broadcast as part of Children in Need. This season saw the departure of companion Nyssa and introduced Turlough. Every story of this season contained an old enemy of the Doctor in at least a minor role, to celebrate the twentieth anniversary of the show.

Regulars

 * The Fifth Doctor - Peter Davison
 * Tegan Jovanka - Janet Fielding
 * Nyssa - Sarah Sutton (departed Terminus )
 * Turlough - Mark Strickson (introduced Mawdryn Undead )

Semi-Regulars

 * Kamelion - Gerald Flood
 * The Brigadier - Nicholas Courtney
 * The Master - Anthony Ainley
 * The Black Guardian - Valentine Dyall

Guests

 * The First Doctor - Richard Hurndall
 * The Second Doctor - Patrick Troughton
 * The Third Doctor - Jon Pertwee
 * The Fourth Doctor - Tom Baker (cameo)
 * Susan Foreman - Carole Ann Ford
 * Sarah Jane Smith - Elisabeth Sladen
 * Romana II - Lalla Ward (cameo)
 * Jamie McCrimmon - Frazer Hines (cameo)
 * Zoe Heriot - Wendy Padbury (cameo)
 * Liz Shaw - Caroline John (cameo)
 * Mike Yates - Richard Franklin (cameo)
 * K9 Mark III - John Leeson (Voice, cameo)

Stories set during this season

 * BFA: Omega (immediately after Arc of Infinity)
 * PDA: Fear (between Arc of Infinity and Snakedance)
 * PDA: Zeta Major (between Arc of Infinity and Snakedance)
 * MA: The Sands of Time (between Arc of Infinity and Snakedance)
 * MA: Goth Opera (between Snakedance and Mawdryn Undead)
 * BFA: Cobwebs (between Terminus and The King's Demons)
 * BFA: The Whispering Forest (between Terminus and The King's Demons)
 * BFA: The Cradle of the Snake (between Terminus and The King's Demons)
 * MA: The Crystal Bucephalus (between The King's Demons and The Five Doctors)

VHS

 * Arc of Infinity
 * Snakedance
 * Mawdryn Undead
 * Terminus
 * Enlightenment
 * The King's Demons/The Five Doctors (extended version)

DVD

 * Arc of Infinity (2007)
 * Snakedance (2011)
 * The Black Guardian Trilogy (contains Mawdryn Undead, Terminus & Enlightenment) (2009)
 * The King's Demons (2010)
 * The Five Doctors - Special Edition (1999)
 * The Five Doctors - 25th Anniversary Edition (2008)

Novels

 * Arc of Infinity
 * Snakedance
 * Mawdryn Undead
 * Terminus
 * Enlightenment
 * The King's Demons
 * The Five Doctors