Gifted in chemistry (despite failing the subject at O-level), she was in her room experimenting with the extraction of nitroglycerin from gelignite when an explosion (later revealed to be a time-storm created by Fenric) swept her up and transported her to Iceworld, many years in the future.

Ace suffered traumatic events in her childhood, including a bad relationship with her mother Audrey (the daughter of merchant seaman Frank William Dudman and his wife Kathleen, who served in the Women's Royal Naval Service during World War II)[10] and the racially motivated Molotov cocktail firebombing of her friend Manisha's flat when she was 13.

Following the latter event, needing to lash out, she burned down a local abandoned Victorian house named Gabriel Chase after sensing the presence of the villain Light there and was put on probation.

Her weapons of choice included a baseball bat and a powerful explosive, disapproved of by the Doctor (who nonetheless found it useful on occasion), she called "Nitro-9", which she invented and mixed up in canisters she carried in her backpack.

What the Doctor is aware of, but Ace is not, is that her arrival on Iceworld was no accident but part of a larger scheme stretching across the centuries and conceived by Fenric,[7] an evil that had existed since the beginning of the universe.

If the series had continued, the production team's intent was to have Ace eventually enter the Prydonian Academy on the Doctor's home planet of Gallifrey and train to be a Time Lord.

[9] A promotional video made to advertise the Blu-ray release of Doctor Who's twenty-sixth season shows Ace as the head of A Charitable Earth.

[12] She appeared in "The Power of the Doctor" celebrating the BBC Centenary, alongside the returning former companion Tegan Jovanka, the two of them now having been hired by Kate Stewart to work as UNIT freelancers.

Ace becomes more and more frustrated with the Doctor's manipulations; he forcibly separates her from a potential relationship with Robin Yeadon in Nightshade and sacrifices her lover Jan to defeat the alien Hoothi in Love and War by Paul Cornell, which proves to be the last straw.

She leaves the TARDIS, joins Spacefleet and fights the Daleks for three years, later rejoining the Doctor and his new companion Bernice Summerfield in Deceit by Peter Darvill-Evans, older and more hardened.

This development in the character was the result of a deliberate decision by Darvill-Evans as the editor of the line at Virgin to change Ace and her role in the ongoing narrative.

When the Monk and his chained Chronovore offer her a chance to return Jan to life, she refuses and rejoins the TARDIS crew, her issues with the Doctor resolved.

In Set Piece by Kate Orman, Ace becomes stranded in Ancient Egypt and comes to realise that she can survive without the Doctor, but that she also increasingly sees the world as he does.

Sophie Aldred has voiced Ace for several audio plays produced by Big Finish Productions, alongside Sylvester McCoy as the Seventh Doctor and, in some stories, Lisa Bowerman as Bernice Summerfield or Philip Olivier as Hex Schofield.

The Reeltime Pictures video Mindgame features Sophie Aldred as "the Human", imprisoned with a Sontaran and a Draconian, the implication being that she is playing Ace, though for copyright reasons this could not be made explicit.

In 2018, Ace was confirmed to appear in Big Finish Production's audio drama based on Doctor Who spin-off Class, with Aldred reprising her role alongside the show's main cast.

In 2020, BBC Books published At Childhood's End (ISBN 9781785944994), a novel by Aldred featuring Ace, decades after her travels with the Doctor and now running the "A Charitable Earth" charity.