Vartex was one of Ravnok's followers. She agreed that the Dryrth needed a crisis to develop. After Ravnok unleashed a virus that killed most of the Dryrth, Vartxk became a criminal. Vartex was the only follower of Ravnok to escape the law. Later, when Ravnok returned to Dryra, Vartex was captured and put on trial with Ravnok. They both escaped shortly after being imprisoned.
On 7 July 2015, Ravnok brought Vartex to the Moon. Years before, Ravnok had buried a container of cheese in a crater, but humans had built a moonbase on top of it. They pretended to be peaceful animals and gained the trust of Freda Jackson, the astronaut in charge of the base. The Fifth Doctor, who was visiting the base with Tegan Jovanka and Vislor Turlough, did not trust them.
After being left alone in a guest room, Ravnok and Vartex came up with a plan to get their cheese by sabotaging the base's nuclear reactor. They cut into the reactor with a high-intensity laser beam, but were caught by Jeffries before they could do damage.
Later that night, Ravnok and Vartex went into the reactor again when they thought everyone else was asleep. This was not true, as the Doctor, Jeffries, and Jackson were waiting for them. Vartex killed Jeffries and Ravnok grabbed the Doctor while he was surprised. Ravnok then handed the Doctor to Vartek and set the base to explode in 20 minutes. Tegan, Jackson, and Turlough stormed into the room and caught Vartex by surprise. Jackson shot Vartex before he could shoot the Doctor. (COMIC: The Lunar Strangers)