K9s Mark I and Mark II correspond with each other.
Mark I wishes Mark II a happy birthday. He tells Mark II that he and Leela are enjoying the social life on Gallifrey. He is very popular. He brags about defeating the Sontarans. He pokes fun at Mark II's life in E-Space.
Mark II replies defensively. He thinks Mark I is "getting above" himself. He brags about the time he, Romana and the Fourth Doctor found the Key to Time. He and Romana are enjoying E-Space, having stopped the charity work. They are seeing the sights and are rather rich.
Mark I responds with a fake apology for offending Mark II. He isn't impressed by the Key to Time, as he can find no mention of such a thing. He has received postcards and letters from the Doctor, who has a new companion. He ends with news that Leela is expecting.
Mark II reports on a terrifying adventure he and Romana have just finished; they are about to start another important quest. He mentions that when Leela and Andred's baby is born, Mark I won't be so popular.
The correspondence ends with Mark I telling Mark II that the Doctor has had a fall and may have to regenerate. He suggests they "bury the hatchet".
- Mark II mentions the Key to Time.
- Mark I says the Doctor probably tripped on his own scarf.
- Mark I attended the inauguration of Chancellor Flavia.
- Mark I mentions the Master is back.
- Mark I says the Doctor has a new companion, a boy.
- The stories in Short Trips: Zodiac are inspired by the signs of the zodiac. This story's theme is Scorpio.
- Mark I mentions a gigantic frozen prawn (TV: The Invisible Enemy) and the potato-headed Sontarans. (TV: The Invasion of Time)
- Mark II and Romana have stopped freeing slaves. (TV: Warrior's Gate)
- Mark I tells Mark II the Doctor has had a fall and will soon regenerate. (TV: Logopolis)
- Leela is pregnant. (PROSE: Lungbarrow)