The microwave-generating mutant adventurer Firestar first learned to control her incredibly dangerous natural powers at the Massachusetts Academy, whose headmistress, Emma Frost (alias the White Queen), emotionally manipulated her in hopes of training her to become an assassin. 

     When Jones discovered the corrupt nature of Frost and the Academy, she angrily departed and tried to resume the life of a normal teenager, refusing an offer of membership from the X-Men; however, she reluctantly returned to adventuring when she was persuaded to become a founding member of the suer-hero youth team known as the New Warriors. 

     Firestar gradually became a more confident and formidable fighter during her time with the Warriors, and she also began a loving, lasting romance with teammate Vance Astrovik (later known as Justice), a relationship that survived a long separation when Vance was jailed for accidentally killing his abusive father. 

  
      When Firestar learned that her microwave powers posed risks to her own health, she became a very reluctant adventurer again. Despite this, she and Justice remained semi-active as superheroes, and were eventually drawn into a conflict with Morgan Le Fay that led to the post-Onslaught reorganization of the Avengers. Justice played a key role in the Le Fay case, and then convinced Firestar to help him capture Whirlwind, a super-criminal who had eluded the Avengers. This prompted Avengers veteran Hawkeye to recommend the young couple for Avengers membership. Justice, a lifelong admirer of the Avengers, eagerly agreed, and an unenthusiastic Firestar accepted the offer as well. The couple were designated reservists at first, but soon upgraded to active membership, filling vacancies in the active roster and moving into Avengers Mansion.

     Before long, Firestar and Justice found their feelings regarding the Avengers reversing. Justice was so anxious about trying to live up to the Avengers' standards that he made himself a nervous wreck, while Firestar grew to like and admire the Avengers, becoming happy with her membership and losing her reluctance altogether when Hank Pym cured the dangerous side-effects of her microwave powers. Firestar became one of the team's most formidable assets, and with her support and reassurance Justice eventually settled in, too, as he learned to regard his fellow Avengers as people rather than icons.

     The couple eventually took a leave of absence to concentrate on their romantic relationship; however, the duo soon infiltrated the suspicious Triune Understanding spiritual organization at the behest of Avengers member Iron Man, gathering information regarding Triune activities. After the corruption of the Triune leadership was exposed, Firestar and Justice returned to the active Avengers roster, participating in the global war against the forces of Kang, but soon stepped down to reserve status. They were among the Avengers who helped maintain global order during the team's conflict with the new Scorpio, when the Avengers temporarily assumed a world leadership role; however, when the Avengers disbanded and reorganized following their conflict with an insane Scarlet Witch, Firestar & Justice did not rejoin the group.