Big Finish Doctor Who/Recap/091 Circular Time

Spring
The Doctor and Nyssa visit a planet of bird-people. They're there to stop the leader of the bird-people, who's ANOTHER renegade Time Lord, but he doesn't want to leave.

Summer
Off to the Tower of London in the 17th century for the Doctor and Nyssa, who've been arrested for forgery, of all things. (The Doctor absent-mindedly gave Nyssa a handful of future coins.) Oh, and the arresting officer was Isaac Newton. Sir Isaac is interested in the coins. Really interested. In fact, he correctly deduces the Doctor's secrets.

Fall
While the Doctor larks about playing cricket in early fall, some time in the early 20th century, Nyssa tries to write... and falls in love.

Winter
Nyssa and her husband must help the Doctor through the bizarre landscape of his mind, as he regenerates on Androzani.

Tropes

 * Historical Domain Character: Sir Isaac Newton
 * Historical In-Joke: Sir Isaac talks about his only speech in Parliament. It sounds like a joke, but it's 100% true: the only thing Isaac Newton ever said in Parliament was a request for someone to shut the window.
 * Journey to the Center of the Mind