Source of Energy

Exploration Stage: Tiger's Spring
From: Conductor
Description: Oh, by the way, the toy power plant came to me in a dream. I never imagined that Martha would ask me to find a toy train... but I'm hoping you can find me a power plant on wheels.
Completed: You found a power plant on wheels? I dreamed about that too, and apparently this is no joke. Apparently the city is really trying to tell me something. Look at this... there's an "E" in the alphabet. Why an "E"? Is it some kind of code?