In her bedroom on board the TARDIS, Nyssa dreams of her long lost home, and a Forbidden Archway that never really existed - or did it?
In the TARDIS corridors she finds a flight of steps, a door marked ‘keep out’, and beyond, a locked room full of secrets. In particular a casket containing a jewel seems to call to her. “Nyssa of Traken, do you want to be my friend?”