Rebecca is the granddaughter of Arthur Hawkins, an old friend of Yugi Muto's grandfather, Solomon Muto. Rebecca encounters Yugi as Yugi returns from Duelist Kingdom. She accuses Solomon of stealing her grandfather's prized Blue-Eyes White Dragon and demanded he duel her for it, when asked about how she knew that Solomon "stole" the card, she replies that Keith Howard told her, although it can be presumed that Keith merely lied to her out of annoyance, indicating that she tried forcing the information out of him. As he was recently discharged from the hospital, Solomon cannot duel, so Yugi duels Rebecca in his place.
While they duel, Solomon recounts of how he met Arthur, an archaeologist who believes that the ancient Egyptians played an ancient form of Duel Monsters. Arthur's colleagues laughed at his strange ideas, and he set out on an expedition with Solomon to find proof. They were trapped when a tomb caved in, and as there were only enough supplies for one person to live, they dueled for them. Now, Yugi and Rebecca are fighting, card for card, the very same duel, and Solomon claims he knows how it will end.
Rebecca discards various monsters to her graveyard to power up her Shadow Ghoul monster, and Yugi concedes defeat. Rebecca demands the card, but Solomon reveals it was destroyed. An angry Rebecca yells at Solomon (unaware that it was really Seto Kaiba that destroyed it) until Arthur arrives, telling her to behave. He shows Rebecca the card Yugi had drawn, and it is a card that would have weakened her Shadow Ghoul for Yugi to destroy and win. (the card was Soul Release which would've allowed Yugi to remove 5 monsters from her Graveyard.) Yugi admits he surrendered on purpose, just as his grandfather did to let Arthur take the supplies. When they were rescued, Arthur was so grateful he gave his Blue-Eyes card to Solomon. After learning about the story, Rebecca quickly apologizes. Yugi gives Rebecca his The Ties of Friendship as a reminder of this lesson, which she keeps ever since.
She and her grandfather return in the Orichalcos arc to help Yugi fight Dartz. Here Rebecca is noticeably older and wearing glasses (to the point that everyone barely recognizes her) and is also in college, much to everyone's shock. She helps by researching Dartz's Three Swordsmen and hacking into Kaiba Corporation's computer system to track others via their Duel Disks. She also seems to be slaving under the delusion that Yugi is her boyfriend (her "darling" in the Japanese version, a reference to Urusei Yatsura), something which makes Téa Gardner jealous. This doesn't seem to be a pretend crush as she has devastated when Yugi's soul was taken and tried to defeat Valon in vengeance, showing she has true feelings for Yugi.
Rebecca also takes part in the KC Grand Championship, where she duels Abe the Monkey Man and Vivian Wong. She loses to Leon von Schroeder in the semi-finals and spends the rests of the tournament cheering from the sidelines. She is absent after the tournament ends, telling Yugi that she will duel him one day and telling Téa (with a coy look) that she will miss Téa.
In the Japanese version of the final episode, Rebecca makes her final appearance by hugging Yugi at the airport while Anzu glares at the scene; the scene does not exist in the English-language version of the episode. This scene is placed in the final episode of the Kaiba Corp Grand Championship.