The USS Enterprise is captured by Trelane, the ruler of Gothos, a childish figure with immense power.

Trelane freezes Kirk and Sulu, then invites them to his castle, refusing to let them leave.

The crew attempts to escape, leading to a confrontation with Trelane.

Kirk realizes Trelane's power source is a mirror and destroys it, freeing the crew.

Trelane's parents intervene, revealing Trelane's childish nature and taking him away for discipline.

The Enterprise escapes, and Kirk classifies Trelane as a "very naughty" small boy.