'The Seeds of Doom' (6 Parts) Story Code '4L' by Robert Banks Stewart

The Doctor is called in by a government minister to investigate the uncovering of two alien seedpods that have been found buried in the permafrost by an Antarctic science team. The Doctor realises that the pods are from an alien creature known as a Krynoid, a hostile form of plant life that infects and transforms all animal life, eventually takes over the planet on which it has landed. The pod opens and infects one of the scientists, but the developing Krynoid is destroyed by a bomb set by Scorby and Keeler, two men sent to retrieve the pods for their boss, Harrison Chase, an eccentric botanist. The Doctor and Sarah, having escaped from the explosion that blew up the base, travel to England. They travel to Chase's mansion in England, where Sarah is captured. Chase opens the pod in controlled conditions, planning to use Sarah as the human host. But when the Doctor rescues her, the plant instead infects Keeler. Chase accelerates Keeler's transformation into a fully-grown Krynoid by feeding him with raw meat. The Krynoid breaks out and goes on a rampage, growing rapidly to gigantic proportions. Chase attempts to kill the Doctor and Sarah by feeding them into a pulverising machine, but the two time travellers escape, and Chase falls into the machine and is killed. UNIT have been called in to deal with the situation, and arrange for the RAF to bomb the Krynoid before it can germinate more of its pods.

Tom Baker (Doctor Who), Elisabeth Sladen (Sarah Jane Smith), Tony Beckley (Harrison Chase) John Challis (Scorby) Mark Jones (Arnold Keeler), Hubert Rees (John Stevenson), John Gleeson (Charles Winlett), Michael McStay (Derek Moberley), Kenneth Gilbert (Richard Dunbar), Michael Barrington (Sir Colin Thackeray), Seymour Green (Hargreaves), Sylvia Coleridge (Amelia Ducat), David Masterman (Guard Leader), Ian Fairbairn (Doctor Chester), Alan Chuntz (Chauffeur), Harry Fielder (Guard), John Acheson (Major Beresford), Ray Barron (Sergeant Henderson), Mark Jones (The Krynoid's Voice)

Produced by Philip Hinchcliffe
Directed by Douglas Camfield

TX:
Part 1 - 26th February, 1976 @ 6.00pm - 6.25pm
Part 2 - 5th March, 1976 @ 5.30pm - 6.55pm
Part 3 - 12th March, 1976 @ 6.55pm - 7h20pm
Part 4 - 19th March, 1976 @ 6.45pm - 7h10pm
Part 5 - 26th March, 1976 @ 6.45pm - 7h10pm
Part 6 - 2nd April, 1976 @ 6.45pm - 7h10pm

Notes:
*Featuring the Fourth Doctor, Sarah and UNIT

*Working titles: 'The Seeds of Death' (until the DWAS pointed out another one in Season 6...)