Narrative Connection
How these two moments in the story relate
Why These Connect
The narrative assertion
"The Doctor's identification of the Keller machine as the source of telepathic impulses at Stangmoor (Part 3) sets up the Master's confrontation with the same machine in Part 4, where the machine's influence directly impacts the Doctor and Master's physical confrontation."
inferred by llm_cross_episode_character
Why This Matters Across Episodes
The longer arc this connection carries
The initial discovery of the Keller machine as a malevolent entity (Part 3) directly enables the Keller Machine's later active role in the Doctor's near-death experience and the Master's manipulation (Part 4), forming a causal chain of escalation in the machine's threat.
About Causal Connections
A directly causes B. The first event sets forces in motion that produce the second. These are the load-bearing connections of plot--remove one and the story structure collapses.