5. The Sound of Drums/Last of the Time Lords
The return of the Master. And more of Captain Jack; I can never get enough of him! It is a very complicated and great plot; suffice it to say that Earth is under attack, the Doctor is reduced to a creature in a cage, and Martha is the only one who can save everyone, which she does. At the core of the episode is the connection between the Doctor and the Master; we see love, anger, jealousy, which pushes the Master to humiliate/seek revenge against his childhood comrade. The anguish on the Doctor's face is so painful to watch. Only those we have loved have the power to decimate us; they know which buttons to push to bring us down.
The Questions: Who has betrayed you? Why? Were there any warning signs? Have you been able to forgive? Has that experience made you more cynical/less trusting of those you know now?