Nadine Crowell came to Port Charles in October 2007 to see her comatose sister, Jolene. Damien Spinelli, a friend of Jolene's, was at General Hospital and filled her in on what transpired prior to Jolene's coma. Nadine was shocked to discover that her sister, a nurse, had been killing patients at General Hospital. It took her some time to come to terms with Jolene's crimes. Nadine, a nurse herself, soon became a member of the General Hospital staff despite her sister's nefarious behavior. It was difficult at first but eventually Nadine managed to win over the respect and friendship of other staff members when they realized that she was a genuinely kind and compassionate person who never judged others.
Nadine worked as an RN at General Hospital and was instrumental in helping Nikolas Cassadine overcome the loss of his love Emily Bowen-Quartermaine. She helped Nikolas construct the Emily Bowen Quartermaine Clinic in honor of Emily as she also worked at the clinic as well as General Hospital. While Nadine was helping Nikolas cope with his loss they eventually fell in love and began to date. Nadine was by his side and willed him to live for his son Spencer when Nikolas was battling a tumor and in return, Nikolas risked everything to save Nadine from being murdered when a serial killer named the Text Message Killer (later revealed to be Diego Alcazar) came to town and began strangling women.
While in Port Charles, Nadine also became good friends with Damian Spinelli and Leyla Mir, a fellow nurse who worked at General Hospital. When the Russian mob came to town and began pushing illegal counterfiet drugs into GH, (that were making patients sick), Nadine partnered up with Nikolas, Lucky Spencer, Sam McCall, and Matt Hunter and together the five of them set out to figure out who was smuggling the drugs into GH and shut them down.
When Emily Quartermaine's identical twin, Rebecca Shaw came to town, the relationship between Nikolas and Nadine slowly began to dwindle because Nikolas felt drawn to Rebecca, as a result of her resemblance to Emily. Nadine realized that she never truly had Nikolas's whole heart, but she loved him and wanted him to be happy. When her family inherited a patent, she came into quite a bit of money and decided the best thing for her would be to leave Port Charles. Nadine met with Nikolas one last time to wish him well and then she left town.