N is for... Nyssa

Nyssa of Traken was the teenage daughter of Consul Tremas, one of the ruling council of the Union of worlds. He had been designated Keeper-Elect, intended to take the place of the aged Keeper who currently supervised the Union using the energies of a bio-electric device known as the Source.

Her mother had died when she was quite, and Tremas had just married a fellow Consul named Kassia. Nyssa inherited one of her duties - the tending of a Melkur in the grove outside the Consul's chambers. These were beings who became calcified on arriving within the influence of the Source if they harboured evil intent. This particular Melkur has survived for many years, whereas most crumble to dust within a short space of time. It proved to be the Master's disguised TARDIS, as he aimed to usurp the powers of the Keepership. He brought Kassia under his mental influence, easily done as she had always been jealously possessive of it.

Despite her genteel upbringing, when Tremas allied himself with the Doctor and Kassia caused him to fall under suspicion, Nyssa was quite prepared to break her father and the time-travellers out of jail, and to stun one of the guards and threaten another with a weapon.

She and Adric then helped devise a plan to sabotage the Source after the Master had taken control over it, sacrificing his servant Kassia to do so.

Once the Master had been defeated the Doctor and Adric left Traken, but Tremas vanished soon after.

Nyssa was then visited by an enigmatic figure in white who helped her contact the TARDIS to inform the Doctor of what had happened. He realised that this was the work of the Master, and sure enough Tremas' body had been taken over by the evil Time Lord.

The white figure then transported Nyssa to the planet of Logopolis to rendezvous with the Doctor and Adric, and she learned the terrible truth of what had befallen her father when she was forced to confront him.

At first, however, she couldn't bring herself to accept that this was not Tremas and the Master was able to use her to threaten Tegan and Adric using a bracelet which controlled movement.

Soon after, she suffered further loss when an entropy field destroyed the entire Traken Union.

Now orphaned and homeless, she therefore joined the others in their travels in the TARDIS, first having to help the newly regenerated Doctor escape a series of traps laid by the Master. Despite knowing Adric slightly longer, and collaborating with him back home, it was with Tegan that she struck up the strongest friendship, whilst the Doctor quickly came to rely on her scientific abilities.

Her role aboard the TARDIS was often that of a mediator and peace-maker.

Captured by the alien Urbankans, she underwent the initial phases of a process to have her mind downloaded into an android body. The Doctor rescued her, but she collapsed soon after because of her ordeal and had to remain resting in the TARDIS during its visit to the planet Deva Loka, linked to a delta wave augmenter.

In 17th Century England, she was given the crucial task of disabling a Terileptil android - which she did by building a device which shook it to pieces.

In the 1920's, again in England, she encountered her lookalike, Ann Talbot. The TARDIS crew were mistakenly invited to a country house where Ann resided. She had a fiancé who was supposed to have died on an Amazonian expedition, but he was really being hidden in the house by his family. He had been driven insane and at one point abducted Nyssa in mistake for Ann.

Nyssa's final time spent with Adric was once more as mediator - when the boy fell out with the Doctor and wanted to return to E-Space. Whilst she was engaged in the TARDIS, he became trapped onboard a space freighter which crashed into the Earth following its seizure by Cybermen. Yet another tragedy she had to face.

In the planet's prehistory, she found herself contacted psychically by a race of aliens who had crash-landed here after fleeing their homeworld. Split into two psyches - good and evil - she was influenced by the better half to help them, coming across the Master once again.

Tegan temporarily left the TARDIS, and Nyssa travelled alone with the Doctor for a short time.

When he was forced to return to Gallifrey and came under sentence of death to prevent Omega from stealing his body in order to transfer from the universe of anti-matter into this one, Nyssa once again betrayed her genteel upbringing by threatening the President of the High Council of Time Lords at gunpoint to try to save him.

After an encounter with the Mara on the planet Manussa, in which Nyssa helped the Doctor single-handedly (due to Tegan's possession by the evil entity), she had a meeting with the Doctor's old friend the Brigadier. The TARDIS picked up a new passenger - schoolboy Turlough - and whilst Tegan did not trust the boy she advocated giving him the benefit of the doubt. He was actually under the sway of the Black Guardian, so Tegan had been right not to trust him - though in the long term he did prove to be a friend to the Doctor. Infected by a mutation, Nyssa and Tegan at one point began to age as the TARDIS moved forward in time - and regressed to childhood when it reversed.

Nyssa eventually left the TARDIS when it arrived at the huge space station known as Terminus. Nyssa contracted Lazar's Disease, but was cured with a dose of radiation. She realised that the process was not being applied effectively, and elected to stay behind and use her scientific knowledge to help refine the treatment.

Played by: Sarah Sutton. Appearances: The Keeper of Traken (1981) to Terminus (1983).

• Nyssa was created by Johhny Byrne specifically for his Traken story, and it was only later that JNT decided to retain her as a companion. As she wasn't created by the production tea, Byrne was paid a fee for every story she appeared in.
• As a later addition, the character is not always best served by stories - either sitting them out all together (Kinda) or being stuck in the TARDIS (The Visitation, Earthshock). She does get a whole story to herself, including a double role for Sutton, in Black Orchid.
• Spin-off material has the Doctor and Nyssa travel for a number of years between Time-Flight and Arc of Infinity, but there is no evidence of this on screen. Quite the opposite, as she retains the same costume (she'll begin changing gear soon after) and they discuss events of the previous two stories as though both have only recently happened.
• If you regard The Collection trailers as canon then Nyssa does have a reunion with Tegan in 2023 - only for it to turn out to be a deception by the Mara.
• Sutton had been a child star, with lead roles in Alice Through The Looking Glass and Brian Hayles' The Moon Stallion.
• Tom Baker used to call her "Miss Basingstoke" when he discovered that she came from there.