The Toy ( audio story ) Publisher ' s summary . 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 ? ” So begins a journey that takes Nyssa from snow capped mountains to vast cities , and introduces her to people she seems to know so well . What dangerous landscape has she wondered into — and can she ever escape to safety , and the comfort of her travelling companions ? Plot . Nyssa wakes from another dream of her time on Traken , and the mysterious " forbidden archway " that she keeps seeing in her dreams . Resolving to tell the Doctor about these dreams , she travels to the console room , only to find the Doctor , Tegan , and Adric arguing yet again . Nyssa instead leaves to go be alone , and breaks down into tears in the TARDIS hallway . Wandering around , Nyssa eventually finds a doorway that is an exact match for the forbidden archway she keeps dreaming of . Ignoring the ornate , " Do Not Enter " sign on the door , she enters the room to find a sort of map room . Examining what appears to be a star chart , she touches one of the stars on there , only for the star chart to show the destruction of that solar system . Horrified , Nyssa backs away , but is startled when a voice begins to call out to her . Nyssa identifies the source of the voice , a small red jewel located in a box . The voice asks her if she would like to get away from her current situation , and implores her to touch the jewel . Hesitantly , Nyssa touches it and is instantly transported to Arcadia , where she meets an old man , who calls her Susan . Confused , Nyssa insists she is not Susan , until a man appears , and claims that he can help Nyssa escape her current predicament . Just as Nyssa is about to help , the old man , now with a younger face implores her not to help . Before Nyssa ' s eyes , the man transforms into a tall old man with white hair , the first Doctor she ever met , before eventually becoming the Doctor she travels with . All the while , the Doctor implores Nyssa not to give in to the Master , who similarly transforms through different forms , including the face of Nyssa ' s father , Tremas . As Nyssa struggles with the Master , she sustains a cut to her face and a part of her hair is cut off . Coming to in the Doctor ' s TARDIS , Nyssa finds the Doctor , Tegan , and Adric standing over her with worry . The Doctor is angered that Nyssa could give in to such a trick , while Tegan and Adric try to defuse the situation . Relenting , the Doctor explains the origins of the red jewel : that it was a toy gifted to his granddaughter , Susan , by a family friend . The Doctor explains that the jewel is a communication node that acts as a telepathic conduit into an intergalactic transdimensional network . He explains that Susan once used the toy too much , and the Doctor had to hide the toy away . After Tegan and Adric leave , Nyssa asks the Doctor if the family friend was the Master , and the Doctor confirms that . Asking the Doctor if the Master is still alive , the Doctor tells Nyssa that the Master has a nasty habit of surviving . The Doctor then replaces the sign on the window , and heads back to the console room with Nyssa .