Muriel Frost worked for UNIT over a twenty-year period, from the 1980s to the 2000s. By the 2000s, she appeared to be also working for the US Army. Over the course of her career, she was a Captain, a Colonel, a Major or a General.
Muriel had a troubled relationship with her boyfriend, Nick. She loved him, in spite of how much they fought, trying to make things better better between them, but he never reciprocated those feelings, often inciting their arguments in the first place. Ultimately, she knew that the relationship wasn't healthy. (COMIC: Evening's Empire)
Working undercover, Frost investigated Stranks, the owner of a night club suspected of selling a potent street drug called Mandrake. At the same time, the Seventh Doctor and Ace had been drawn to Earth by the alien energy structure known as the Mandragora Helix. It had contacted Stranks and used him to produce Mandrake, which sapped the will of its users and made them susceptible to the Helix's influence. The Doctor and Ace worked with Frost to thwart the Helix again. During the course of this venture, she received a field promotion to Colonel. (COMIC: The Mark of Mandragora)
In the 1990s, she, Corporal Ives and UNIT helped the Seventh Doctor investigate a crashed Nazi plane from World War 2 in Middlesbrough, which the Doctor suspected had something to do with a UFO. She and two other UNIT personnel did a dive to the bottom of a river, finding the plane quickly, though Frost had a feeling it was waiting for her. Meanwhile, Ace was kidnapped by Alex Evening. That evening, the plane was removed from the river, and the body of the dead pilot was brought to a secure place, and Frost was wired up to a machine, built by the Doctor, to let her talk to te deceased pilot. The experience was tough for her, as the German pilot was able to read her mind, becoming privy to her uneasy relationship, though the pilot did try to console her. Afterwards, she was able to confirm that there was a UFO involved, but she also wanted to destroy the machine.
After stopping by the Burroughs Charted Surveyor so the Doctor could look for Ace, Ives drove Frost back to her flat, while the Doctor went off by himself. Inside, Nick started another fight with her, and even though she tried to get him to open up, he decided to nastily tell her that he pictured other people while having sex with her. Anger filled her, driving her to aim a gun at his head, but despite him goading her and even a dark part of her psyche longing to pull the trigger, she was interrupted by a ringing telephone. It was Ives, calling her to inform her that the Doctor found the UFO and to get her away from Nick.
At Alex's home, Frost was initially annoyed with the Doctor for being strung along, but was quietened when the Doctor showed her the UFO, a Q'Dhite Mind-Treader, which was smaller than she expected. After explaining that the Mind-Treader was designed to create new realities, and that Alex had used it to make one of his own, the Doctor lead them into his TARDIS, gathered a company of UNIT soldiers, and headed off to put an end to Alex's havoc. In a city created by Alex, Frost, Ives, and the UNIT soldiers fought against the locals, before Frost and Ives split off to aid Ace, whom Frost had located. However, when confronting Alex, he commanded a monstrous bible to attack and kill Ives. After she was killed, the Doctor went back to Earth and returned with Janice Evening, Alex's deeply religious mother, who reprimanded him, causing Alex's world to shatter. Frost evacuated the crumbling reality with the Doctor and the other survivors, and left after the Doctor took the Mind-Treader from the Evenings' shed. (COMIC: Evening's Empire)
After the London UFO crash on 6 March 2006 (TV: Aliens of London) or 28 June 2006, (PROSE: Operation London) Major Frost and her Geneva EVA team (PROSE: Number Ten) were summoned to 10 Downing Street (TV: Aliens of London) from Geneva. (PROSE: Operation London) The Doctor, Rose Tyler, and Mickey Smith saw a news broadcast on the arrival of the experts which had been picked up on the TARDIS scanner, and Frost was visible on the left. The Doctor immediately identified them as UNIT, noting that they were "good people". (TV: Aliens of London)
She was summoned to be an advisor on extraterrestrial activity, coming dressed in her US Army Major uniform. During the meeting, she sat next to General Schwartz and, contrary to the rest of her colleagues, was intrigued rather than disturbed by the Ninth Doctor's conclusion that the crash had been faked so as to draw out and assassinate the experts. Unfortunately, he was proven right when the aliens unmasked and identified themselves as the Slitheen family, specifically Asquith Slitheen and Jocrassa Fel-Fotch Passameer-Day Slitheen, and they summarily used electrocution via the experts' ID cards to execute them. (TV: Aliens of London) Major Jenny Maguire shortly after officially announced her and her team's death on an operations board to other UNIT officers. She had to inform the families of the deceased, and later saw the coffins off an air strip. (PROSE: Number Ten)
Fiery in both hair colour and temperament, Frost was a no-nonsense and efficient UNIT operative who had problems maintaining personal relationships. (AUDIO: The Fires of Vulcan) Major Jenny Maguire, who was familiar with Frost, joked that "[she would] like to see anyone face her down", referencing her temperament. (PROSE: Operation London)
Muriel Frost was outwardly confident and brave, always facing challenges head on; she took enthusiasm in undertaking challenging tasks, such as diving, using untested machinery built by the Doctor to let her communicate with the dead, and even when faced with the dead, she never backed down from her motivations, acting like a "warrior", not giving in to fear. She didn't appreciate being strung along, and would confront those who did.
In her home life, she faced constant abuse from her boyfriend, Nick, who would deliberately start fights. She would try to not let his comments, his insults, affect her, but they always managed to do so. She would try to get him to talk, to try to fix their problems, but these actions were never reciprocated. She knew the relationship was troubled. She knew it wasn't healthy. But she still loved him. (COMIC: Evening's Empire)
Major Frost, in her final minutes, displayed intrigue at the Doctor's conclusion that the crash had been faked to lure Earth's alien experts into a deadly trap, as opposed to the other experts, who were more peturbed. (TV: Aliens of London)
Fairskinned and slim built, (COMIC: Evening's Empire) Frost had distinct firey-red hair, (COMIC: Evening's Empire, AUDIO: The Fires of Vulcan) with an angular face complete with arching eyebrows and prominent cheekbones. (COMIC: The Mark of Mandragora, Evening's Empire, TV: Aliens of London) She had either blue (COMIC: Evening's Empire) or brown eyes. (TV: Aliens of London) She had ear piercings. (COMIC: The Mark of Mandragora, TV: Aliens of London) By the time of Frost's death, however, she had black hair. (TV: Aliens of London)
Behind the scenes
- According to REF: DWMSE 11, in early drafts of 2005's Aliens of London, the Ninth Doctor specifically named one of the experts, stating: "General Muriel Frost. Strategic Adviser to the United Nations Intelligence Taskforce. Good woman." Curiously, the script described her of being thirty-five years of age, at odds with such stories such as AUDIO: The Fires of Vulcan, which showed her working for UNIT in 1980 — therefore, going by the age given in Aliens of London, Frost would've been around nine years old.
- In the final cut of the episode, the nametag "FROST" is still visible on her uniform.
- The same issue also gave a list of uncredited actors for the smaller roles, potentially including the as-yet-unidentified actress for Frost in Aliens of London.
- PROSE: Operation London and Number Ten, two short stories that were released to coincide with Aliens of London and World War Three, explicitly references Frost by her surname.
- The 2005 Classified! A Confidential 3-D Dossier activity book included a closing note from General Muriel Frost.