Mary Margaret Stone arrived in Pine Valley to find out more information about her twin sister Frankie's death. Upon arriving, Maggie reconnected with her family, Vanessa and Leo, who she barely knew.
Maggie was in town only a few hours she crossed paths with Bianca Montgomery. Bianca fainted upon seeing who she believed to be her dead lover. Maggie discovered that Frankie had been killed by their aunt, Vanessa Cortlandt. When Maggie confronted Vanessa, Vanessa attacked and drugged her. Vanessa tied the young woman to a wheelchair and left her for dead in an abandoned pump house near Willow Lake. Luckily, David and Leo found her in the nick of time.
Maggie eventually embraced David and Leo, and later Trey. Maggie also grew close to Bianca, after some initial discomfort that Bianca saw her as gay or wanted to pursue a relationship with her. Maggie overcame those concerns when she saw other girls tormenting Bianca. To Bianca's shock, Maggie asked Bianca to go to the prom. They had a wonderful time and continued to grow more attached. Bianca was afraid that she might be using Maggie as a replacement for Frankie and pushed Maggie towards Tim Dillon. Although Maggie dated Tim a few times, she felt a deeper connection with Bianca. When Leo was killed, Bianca comforted Maggie. Their level of emotional intimacy grew and Bianca confronted Maggie about how far that intimacy should go. Maggie admitted that she did have some sort of feelings for Bianca, but she still considered herself heterosexual and could not in good conscience pursue a romance with Bianca. Although both young women were saddened, they pledged to remain friends no matter what.
David offered to pay for Maggie's expenses for college, and she agreed. Enrolling at PVU, she had a tough time with fellow student Henry Chin, who was her lab partner in chemistry class. Henry could be brusque and cold, but Maggie found him interesting and slowly began to chip away at his emotional walls. After a passionate kiss in her dorm room, she realized the feelings she had developed for him were mutual and they began dating. Unfortunately, his traditional, old-world Chinese family was unhappy about their romance. Henry's mother thought that Maggie was distracting him from his goal of being a doctor by encouraging his real passion for music. When Maggie and Henry were taking a test in chemistry class, Maggie allowed Henry to cheat off of her exam so he wouldn't fail. Not long after, the teacher accused Maggie of cheating off Henry's exam. The teacher assumed Maggie was the cheater because her grades were not as high as Henry's. Shocked and hurt by the accusation, Maggie went to Henry and asked him to turn himself in. Henry told Maggie that if did that he would be dishonoring his family. When Henry refused to take responsibility Maggie ended the relationship immediately. Maggie was facing expulsion from when Henry admitted that he was the one who cheated. The teacher apologized to Maggie and told her that she would be able to stay at PVU. Although Maggie was grateful Henry decided to turn himself in, she could not find it in her heart to forgive him and their relationship was over.
In the summer of 2003, Maggie showed how deep her friendship with Bianca was after Bianca was raped by Michael Cambias. Bianca kept the rape a secret, although everyone noticed the drastic and unhealthy changes in her behavior. In order to cover up her rape, she told everyone that she was upset because she had broken up with Lena. Bianca did indeed end her relationship with Lena, but couldn't tell her about the rape. Weeks later, Bianca finally admitted to Maggie that she had been raped. Maggie wanted to tell the cops, but Bianca made her promise on their love of her sister, Frankie she would not tell anyone what happened.
After a long discussion with David and the kind words from Kendall, Bianca decided not to terminate the pregnancy. She confessed to Maggie that she wanted to keep the baby because it may be her only chance to have one. Maggie didn't completely agree, but stood by her and encouraged her to tell her mother the truth. Bianca refused to tell Erica about the pregnancy for fear that it would destroy her. She knew that if she told her mother the truth, she would always resent the baby because the child would be a product of rape. Bianca told Maggie that, with David's help, she would hide the pregnancy and go away to have the child. When she returned with the child she would tell everyone that the baby was adopted. Maggie thought her plan was extreme, but promised to keep the pregnancy a secret.
During a tender moment at home, Maggie surprised both herself and Bianca by giving Bianca a passionate kiss. Shocked and confused, Maggie fled and never spoke of the kiss again.
During Bianca's final few months of pregnancy, Maggie casually dated Jamie Martin while Bianca had resumed her relationship with Lena. When Bianca was told her baby was stillborn and Lena left town, Maggie was a major support system for Bianca. In summer 2004 Maggie professed her love to Bianca and asked her if they could begin a romantic relationship. Bianca was moved but gently told Maggie that she was still recovering from her losses and she also didn't want to force Maggie into a situation that she might later regret. Maggie was devastated and began to distance herself from Bianca. She met Ryan Lavery's brother Jonathan, a handsome, brooding young man who treated Maggie with respect and devotion.
Or so Maggie thought. In reality, Jonathan was an abuser who hated her friendship with Bianca. He did everything he could to isolate Maggie from Bianca. After they moved in together, Jonathan proposed. Maggie was confused and emotionally drained, but accepted his proposal. Jonathan began verbally and physically abusing Maggie. Bianca suspected that things weren't well with her old friend, but Maggie rejected her concerns. But finally, when Bianca and Jackson Montgomery brought Jonathan's ex-girlfriend to town and she told Maggie about all the abuse she went through, Maggie woke up. She dumped Jonathan, and took him to task for his abuse against herself and her friends. Due to the lack of evidence, Maggie decided not to press charges against him.
Shortly after Maggie freed herself from Jonathan, Bianca decided to move to Paris with her newly recovered daughter, Miranda. Bianca asked Maggie to go with her, saying Maggie could share her suite or could rent a place of her own and attend University. Maggie declined, claiming that she didn't want to add even more upheaval to her life. But after Bianca's farewell party, Maggie realized that the happiest moments of her were the time she spent with Bianca and Miranda. She raced to the airport and managed to get on board the Cambias jet in the nick of time. Both women agreed that their relationship defied explanation, but they loved each other deeply. They pledged to be there for each other in every sense, no matter what. When Bianca returned for a visit to Pine Valley, she told everyone that she and Maggie were an official couple in Paris.
Bianca returned to Pine Valley shortly before Thanksgiving, 2006. She had brought her daughter Miranda with her for an extended visit. She finally admitted that she had fled from Paris, heartbroken because Maggie had an affair with another woman. Before long, Maggie showed up on Bianca's doorstep in Pine Valley. Maggie had realized that the only woman she loved was Bianca, and she wanted to give their relationship another try. Although Bianca still had deep feelings for Maggie, she wasn't ready to resume their relationship and return with her to Paris. Before Maggie left Pine Valley she had a confrontation with Zarf, who had romantic intentions regarding Bianca. Zarf was biologically male, but identified himself as a transgender lesbian. Maggie warned him not to hurt Bianca, and told him that she loved Bianca, and wasn't ready to give up on her. Maggie bid Bianca a tearful goodbye, promising to stay in touch, and returned to Paris.