Madeline first appears at General Hospital, and visits Dr. Silas Clay, who is revealed to be her son-in-law. Madeline confronts him about trying to visit Nina, Silas' wife and Madeline's daughter, at the institution where she was being held after going into a coma. Madeline believes Silas is responsible for Nina's condition, who is in a coma as a result of overdosing on antidepressants. Silas steadfastly insists he's not responsible, and wasn't interested in getting Nina's money. Madeline, though, tells him she knows about his affair with Ava Jerome, and his daughter, Kiki, born as a result of this affair. She tells him to sign over his claim to Nina's inheritance. Silas says he will give up Nina's money if he finds out where Nina is. Madeline refuses to tell him, and Silas says he won't sign the papers until he gets some answers.
Madeline later meets Nathan West, and it's revealed that he is her son and Nina's brother. He is a cop now investigating Nina's attempted murder, hoping to finally arrest Silas for trying to kill Nina. However, he doesn't have any proof. Madeline wants Nathan to prove Silas' guilt, believing that Silas was only interested in Nina's money. Nathan hasn't seen Nina in years after Madeline had her moved to another facility, but she later tells Nathan that Nina is dead. Nathan later tells Madeline he's beginning to suspect that Ava was the guilty party, not Silas.
Nathan puts a plan in motion to catch Nina's killer, and is shocked when it's revealed to be Madeline. Nathan confronts her, along with Silas and Sam Morgan, Silas' girlfriend. Madeline reveals she wasn't trying to kill Nina, but Nina's baby. Madeline knew about Silas' affair with Ava, and showed proof to Nina. However, Nina revealed she was pregnant, and believed Silas would come back to her and leave Ava. Madeline paid Nakamura, Nina's pharmacist, to fill a prescription of Nina's of antidepressants that would force Nina to miscarry. But the dose ended up putting Nina in a coma, and Madeline pointed the finger at Silas so Nathan would go after him. When Nakamura felt guilty about keeping the secret, Madeline killed him to cover her tracks. Nathan arrests Madeline, disgusted at her actions.
In the holding cell, Madeline is put across from Dr. Liesl Obrecht, and it's revealed the two women are sisters. Madeline West was born Magda Westbourne, and left behind Liesl and her life in Zürich, Switzerland, where the sisters grew up. The two share animosity towards each other, but the two both reveal they were trying to help their children when they were arrested. Nathan later comes in, and reveals that his father disinherited him and Madeline from his will, and left everything to Nina. After he leaves, it's revealed that Nathan is actually Liesl's biological son. Madeline tells Liesl to stay away from Nathan, because she tried to give him up, and Madeline stepped in and raised Nathan herself. Liesl, though, is determined to get to know Nathan, and to tell him the truth. The next day, Nathan comes to Madeline's cell, and revealed that he met Britt Westbourne, Liesl's daughter, the previous night, and he brought her back to his place. Madeline is shocked, and asks if they slept together. Nathan says they didn't, but Madeline tells him he can't sleep with Britt because she's his sister, and Liesl's his mother. Nathan leaves, shocked by this.
Madeline is transferred to prison to be held until she stands trial. Before she goes, she tells Nathan that she lied, and Nina is actually alive. She claimed that Nina was dead so she could get ahold of the inheritance her husband left to Nina. Nathan asks where Nina is. Madeline doesn't tell him, insisting she doesn't want him to be charged as her accomplice. Before she is transferred, Silas comes, and she coldly tells him that even though she's in prison, she's content to know that he will never see Nina again.