Within a "star desert" the crew encounter the odd, storm-wracked planet Gothos. Then Kirk and Sulu disappear from the bridge. The planet's sole inhabitant is the foppish Trelane, who lives in a manor house be believes represents modern Earth, but which is actually centuries out of date. He has plans for the crew, and the power to ensure that he gets what he wants. Kirk manages to thwart him, but it's only temporary: Trelane moves Gothos itself to intercept the fleeing starship! Against that kind of power, Kirk will need all his wits...