The Church of Saint Sebastian (short story)

Summary
Christmas 1016. The Church of Sebastian holds a terrible alien secret. The Doctor and Nyssa arrive in a small English village to find themselves at the centre of time itself. They're not the only visitors in town. Millions of alien races arrive, demanding control over the great key. The Doctor discovers how one key can distroy the entire cosmos and is powerless to stop it.

Characters

 * Fifth Doctor
 * Nyssa

Continuity
to be added

Timeline

 * This story occurs after ST: Saturn
 * This story occurs before BFA: Spring (audio story)