Season 18
The season featured a story arc involving E-Space and the return of the Master who had stolen a new body rather than regenerate. The stories were darker and more adult in tone than those during the Graham Williams era. They also attempted to emphasise science, much to the satisfaction of both script editor Christopher H. Bidmead and executive producer Barry Letts. Notably, this season revolves around the theme of entropy, linking together all of its stories in a rare phenomenon for the show (while other story arcs would be linked together via people, objects, etc, the use of an overarching theme for a season was unprecedented). This theme would eventually foreshadow and culminate in the Doctor's regeneration at the end of the season.
All Episodes
S18 E1: The Leisure Hive (1)
S18 E2: The Leisure Hive (2)
S18 E3: The Leisure Hive (3)
S18 E4: The Leisure Hive (4)
S18 E5: Meglos (1)
S18 E6: Meglos (2)
S18 E7: Meglos (3)
S18 E8: Meglos (4)
S18 E9: Full Circle (1)
S18 E10: Full Circle (2)
S18 E11: Full Circle (3)
S18 E12: Full Circle (4)
S18 E13: State of Decay (1)
S18 E14: State of Decay (2)
S18 E15: State of Decay (3)
S18 E16: State of Decay (4)
S18 E17: Warriors' Gate (1)
S18 E18: Warriors' Gate (2)
S18 E19: Warriors' Gate (3)
S18 E20: Warriors' Gate (4)
S18 E21: The Keeper of Traken (1)
S18 E22: The Keeper of Traken (2)
S18 E23: The Keeper of Traken (3)
S18 E24: The Keeper of Traken (4)
S18 E25: Logopolis (1)
S18 E26: Logopolis (2)
S18 E27: Logopolis (3)
S18 E28: Logopolis (4)