The Doctor and Jamie are part of a celebratory throng of people heading toward the TARDIS. Waiting for them are King Gavin XXIII and his retinue of guards. The king gives a speech praising the Doctor and Jamie for helping him defeat his "evil" brother Conrad. As the Doctor and Jamie prepare to leave in the TARDIS, the people decide to build a giant statue of their king to block the view of the Tower of Judgement, where Conrad now resides.
In the TARDIS, the Doctor and Jamie are congratulating themselves on finally being appreciated instead of having to skulk away. The TARDIS lands, and they appear to be in the same place, though it's clear to the Doctor that at least some time has passed. They see the giant statue, now built, but instead of Gavin's head, it is Conrad's. The Tower of Judgement has been destroyed.
They are greeted by Ernst, who takes them to his place for tea. They learn that it's been ten years since they were last here. On information received from Ernst and his friend Geffre, they learn that they are credited with defeating the evil Gavin and restoring King Conrad to the throne.
Sitting outside by themselves, the Doctor and Jamie discuss the situation. The Doctor feels something is wrong, though Jamie is inclined to leave things as they are, as the people seem happy. Jamie suddenly notices the stars are different from what they were the last visit, and the Doctor realises that they have landed on two doppelgänger worlds: one with Gavin as king, and one with Conrad as king. Jamie points out that, though mostly identical, there is one difference: the king. They worry that the Gavin they restored to the throne on the first planet may be the same tyrant as the one on this planet.
They return to the first planet several years after the previous visit, and talk to Ernst. Things are going well. However, the Doctor has a plan.
He brings the king of each world onto the TARDIS to meet each other. Of course each king thinks he is seeing his evil brother. They object to being in the other's presence, but listen to the Doctor. He suggests they should work together. They are stubborn, and even Jamie doesn't think it will work. The Doctor finally asks each one what is wrong with his brother, and the answers surprise him. Gavin says Conrad eats with his mouth open, and Conrad says Gavin breathes "in a really annoying way".
The Doctor leaves them to enjoy their arguing, and eventually brings each back to his own planet. Enjoying a holiday on Gavin's planet, Jamie wonders to the Doctor who put Conrad in power on the other planet: themselves in the future or another version of themselves?
- This was Tony Keetch's first Doctor Who prose story.
- The stories in Short Trips: Zodiac are inspired by the signs of the zodiac. This story's theme is Gemini.
- The title alludes to the television serial Twin Peaks.