Circular Time (audio anthology)

Publisher's summary
Summer to winter, the seasons turn.

In the springtime of a distant future, the Doctor and Nyssa become embroiled in Time Lord politics on an alien world. During the stifling heat of a summer past they suffer the vengeful wrath of Isaac Newton. In the recent past, Nyssa spends a romantic golden autumn in an English village while the Doctor plays cricket. And finally, many years after their travels together have ended, the two friends meet again in the strangest of circumstances.

Four seasons. Four stories.

Now close the door behind you, you're letting the cold in...

Spring

 * The Doctor - Peter Davison
 * Nyssa - Sarah Sutton
 * Hoodeye - Jamie Sandford
 * Redklaw - Toby Longworth
 * Carrion - Lois Baxter
 * Snowfire - Teresa Gallagher
 * Zero - Hugh Fraser

Summer

 * The Doctor - Peter Davison
 * Nyssa - Sarah Sutton
 * Guard - Jeremy James
 * Molly - Sunny Ormonde
 * Jailer - Trevor Littledale
 * Sir Isaac Newton - David Warner

Autumn

 * The Doctor - Peter Davison
 * Nyssa - Sarah Sutton
 * Andrew - Jamie Sandford
 * Jack - Toby Longworth
 * Anton - Jeremy James
 * Don - John Benfield

Winter

 * The Doctor - Peter Davison
 * Nyssa - Sarah Sutton
 * Lasarti - Jeremy James
 * Anima - Sunny Ormonde

Continuity

 * Nyssa and the Doctor make reference to the events of DW: Logopolis, as well as the cause of the Second Doctor's regeneration into the Third Doctor.
 * The Doctor mentions the events of (DW: The Caves of Androzani), and Peri.

Timeline
Placing Circular Time within a timeline is somewhat complicated, given that it is in 4 parts. Thus the following is supposition based on the dialogue.

Spring

 * Spring occurs at some point (early) after: DW: Castrovalva.

Summer

 * Summer occurs at some point after: DW: The Visitation

Autumn

 * Autumn occurs after: ST: The Church of Saint Sebastian.
 * Spring, Summer, & Autumn occur before ST: Greenaway

Winter

 * Winter occurs for Nyssa a long time after: DW: Terminus.
 * Winter occurs for the Doctor during his regeneration in DW: The Caves of Androzani.