Under a Yellow Sky is about some of the things Marion has to get used to now she has come to live on Gallifrey for good. She has to get used to a different colour sky and she needs a new watch because there are thirteen hours in the day. She also has to get used to being served by maids and butlers. Marion is stepping up the social ladder as well as moving to another planet.

Red grass and yellow skies came into the equation because of the description of Gallifrey that The Doctor gave to Martha in the story ‘Gridlock’. I refused to put in an extra moon, because that completely undid everything I had written up to now. But red grass could be accommodated by putting it in the valleys and mentioning that alien green grass had ousted it in many other parts of the planet. It happened to red squirrels on Earth, so why not?

At this point I also introduced some elements of Gallifreyan society that I thought necessary. Gallifrey is an alien planet. Why would it have days of the week, months of the year the same as Earth.

“I am… on a planet where the sun sets in the east and rises in the west. There are twenty-six hours in the day, seven days in the week, called Lunar, Thrum, Woe, Thetic, Fris, Stón and Sóre. There are twelve months in the year. Each month is exactly thirty seven days long. There are five weeks and two days in each month. The months are called Janus, Fibster, Melcus, Avry, Mí, Jute..” She paused a few moments as she ran the names of the months through her head. “Jule, Accrion, Setpima, Octima, Samavan and Decima..”

Days of The Week
Lunar
Thrum
Woe
Thetic
Fris
Stón
Sóre

Months of The Year
Janus
Fibster
Melcus
Avry
Mí
Jute
Jule
Accrion
Setpima
Octima
Samavan
Decima

It all contributes to the alienness of Gallifrey and how out of her depth Marion might feel from time to time.

Lapins get mentioned a lot in my stories. They are like rabbits but without long ears and buck teeth, and they shed their coats which can be made into furs for Gallifreyan ladies to wear, which is, for Marion, the nicest difference between Gallifrey and Earth – on Gallifrey she can wear a fur coat without feeling guilty.

Incidentally, the maid, Rika, is going to be important in later stories.