The two first meet in Palas when the Crusade lands, and at first they clash with each other. Hitomi feels jealous about Millerna's flirtation with Allen upon her arrival, seeing them, the princess and the knight, as the perfect couple. Millerna mistakes her for Allen's servant and, after giving her a dress to wear in Palas, points out her odd clothes and short hair. When Hitomi discovers Millerna embracing Allen on the rooftop, Millerna notices her, and kisses Allen in front of Hitomi.
After Millerna discovers that Allen is the biological father of Chid Freid, she feels conflicted about her feelings for Allen, which is further complicated by the arrival of her betrothed, Dryden. She goes to Hitomi and attempts to ask for advice under the guise that she needs help for her "friend" who is trying to decide between two men, a playboy who fathered a child and a rich, nice man. Hitomi expresses annoyance with the playboy's behavior, and suggests several solutions to Millerna's problem, including giving her a tarot reading, but not realizing who the story is about. When Merle asks Hitomi to decide whether she really likes Van or Allen, she says that she likes Allen and that she's just worried about Van, and Millerna protests that Allen is out of her league.
Back in Asturia after Hitomi, Van, and Allen's escape from Zaibach, Dryden tells the three of them that he and Millerna are going to get married. Millerna looks through her closet for dresses for Hitomi. Hitomi tries to tell Millerna that she doesn't have to give up on Allen, even though she is conflicted because if Dryden and Millerna were to get married, Allen would be single. Millerna asks Hitomi for a reading, and Hitomi, afraid of what the cards will predict and conflicted about her own feelings for Allen, runs away.
The day before the wedding, Millerna confronts Hitomi and asks her to give her a reading. Hitomi goes through with the reading, but sees a vision of Allen and Millerna together, and realizes that the marriage is a mistake. To try and allay Millerna's fears, she switches two tarot cards, thus giving her a false "good" reading and encouraging her that she will find happiness with Dryden. After Naria and Eriya attack and Millerna is tending to Dryden's wounds, Hitomi tells Millerna the truth that the cards said the marriage was a mistake, and that Allen is the right man for her, but that she didn't want to lose Allen because she loves him. When the attack subsides, Millerna apologizes to Hitomi for asking her to do a reading, feeling that she made her friend suffer.
When Allen proposes to Hitomi, he tells her the truth about Chid, which shocks her. She goes to consult Millerna, and tells her about a "friend of hers" and soon realizes that Millerna knew what happened, too. Millerna says that you can't change what people did before you met them, and Hitomi believes that Millerna still loves Allen.
Upon Hitomi's return to Earth, her experiences with Millerna and conflicted feelings about Allen and Van lead her to realize that she was ignorant of Yukari's own feelings for Amano, which led her to tell Hitomi that she should tell him how he felt, rather than acting on her own feelings.
