Season 21
The Twin Dilemma, the first story with Colin Baker as the Sixth Doctor, aired last in the season. This season saw the departure of companions Tegan, Turlough and Kamelion and introduced Peri. Most episodes were the traditional twenty-five minute length. However, due to coverage of the 1984 Winter Olympics, Resurrection of the Daleks was re-edited before airing and shown as two forty-five minute episodes.
Episodes
1 Warriors of the Deep (1) Jan 5, 1984 
2 Warriors of the Deep (2) Jan 6, 1984 
3 Warriors of the Deep (3) Jan 12, 1984 
4 Warriors of the Deep (4) Jan 13, 1984 
5 The Awakening (1) Jan 19, 1984 
6 The Awakening (2) Jan 20, 1984 
7 Frontios (1) Jan 26, 1984 
8 Frontios (2) Jan 27, 1984 
9 Frontios (3) Feb 2, 1984 
10 Frontios (4) Feb 3, 1984 
11 Resurrection of the Daleks (1) Feb 8, 1984 
12 Resurrection of the Daleks (2) Feb 15, 1984 
13 Planet of Fire (1) Feb 23, 1984 
14 Planet of Fire (2) Feb 24, 1984 
15 Planet of Fire (3) Mar 1, 1984 
16 Planet of Fire (4) Mar 2, 1984 
17 The Caves of Androzani (1) Mar 8, 1984 
18 The Caves of Androzani (2) Mar 9, 1984 
19 The Caves of Androzani (3) Mar 15, 1984 
20 The Caves of Androzani (4) Mar 16, 1984 
21 The Twin Dilemma (1) Mar 22, 1984 
22 The Twin Dilemma (2) Mar 23, 1984 
23 The Twin Dilemma (3) Mar 29, 1984 
24 The Twin Dilemma (4) Mar 30, 1984