Season 2
Milestones this season included not one but two encore appearances by the Daleks; the departure of the original three companions, Susan Foreman, Barbara Wright and Ian Chesterton; and the first appearance of someone else from the Doctor and Susan's home planet, and the first Time Lord enemy to appear.
All Episodes
S2 E1: Planet of Giants
S2 E2: Dangerous Journey
S2 E3: Crisis
S2 E4: World's End
S2 E5: The Daleks
S2 E6: Day of Reckoning
S2 E7: The End of Tomorrow
S2 E8: The Waking Ally
S2 E9: Flashpoint
S2 E10: The Powerful Enemy
S2 E11: Desperate Measures
S2 E12: The Slave Traders
S2 E13: All Roads Lead to Rome
S2 E14: Conspiracy
S2 E15: Inferno
S2 E16: The Web Planet
S2 E17: The Zarbi
S2 E18: Escape to Danger
S2 E19: Crater of Needles
S2 E20: Invasion
S2 E21: The Centre
S2 E22: The Lion
S2 E23: The Knight of Jaffa
S2 E24: The Wheel of Fortune
S2 E25: The Warlords
S2 E26: The Space Museum
S2 E27: The Dimensions of Time
S2 E28: The Search
S2 E29: The Final Phase
S2 E30: The Executioners
S2 E31: The Death of Time
S2 E32: Flight Through Eternity
S2 E33: Journey into Terror
S2 E34: The Death of Doctor Who
S2 E35: The Planet of Decision
S2 E36: The Watcher
S2 E37: The Meddling Monk
S2 E38: A Battle of Wits
S2 E39: Checkmate