2. Genesis Of The Daleks 12.11-12.16
Genesis of the Daleks is truly momentous in as number of ways. Principally, because it establishes the back story of the Doctor's greatest enemy the Daleks. We understand, better than ever by this story's close, who they are. The circumstances of their creation explain why they are so bent on purity and elimination of the other, and even why they use the word exterminate. This is the first story to feature the Dalek's creator Davros. This story serves to answer why anyone would create the Daleks. The backdrop of the thousand years multi-era war of the original human inhabitants of Skaro, is supposed to be solved by Davros's great peace creation. But Davros himself mad with power wants to rule "above gods" and would gladly destroy all life everywhere for that purpose. Thorny moral discussions concerning the price of peace make this an especially weighty serial, as it strives to answer whether any price is too high, whether any course of action is too extreme. While the many war-centered stories of Doctor deal with this issue to varying degrees, here it becomes the focus of the story. In a superb twist of irony, both Davros and the Time Lords seem to agree that there is no price too high with the latter being willing to subvert the creation of the Dalek race, just to achieve such an aim. The Doctor famously wonders whether such a right is given to any person or group, whether anyone can really decides with clear conscience who should live and die. While the serial is wrapped neatly for the characters, by and large, the moral question seems to remain somewhat open. I think this serial is a major shift for the Doctor as well. So much of early Doctor Who is focused more on an idea akin to 'let us get out of this mess', indeed the original rule one was to never rewrite history. Then as we transition to previous incarnation he is under the control of UNIT. Here in some ways is the first step of the Doctor choosing his own destiny, even while hired as the world's ultimate contract killer.