Andrea Barnes (Tara Rosling) is a villainess from "Unfit," episode 3.10 of Ransom (airdate May 4, 2019). She is the wife of Benjamin Barnes.
The couple lived next door to Kaylee Hobbs, a recovering addict whose infant son, Finn, was abducted. Cri-Res was on the case, and the investigation saw Eric Beaumont and Zara Hallam pose as a married couple while encountering Andrea and Benjamin, whose house appeared to be set up for a family. The main suspect was originally a notorious kidnapper known as the Sandman, only for Eric to reveal that the Sandman actually died months before Finn's abduction. Later on, Oliver Yates uncovered video of the abduction, which revealed that Finn's kidnapper was none other than DCI Leo Turner--who was the lead investigator on the Sandman case.
Afterwards, it was uncovered that Turner and Benjamin were army buddies, which led to the reveal that both Benjamin and Andrea were in on the kidnapping scheme, which was supposed to result in Finn going to the couple. Andrea's past revealed that her mother was an addict, and seeing Finn with Kaylee led her to believe that Kaylee was an unfit mother and would traumatize Finn. Meanwhile, their plans to adopt fell through when Benjamin's psychiatric problems led to the couple being rejected. Feeling betrayed by the country he once served, Benjamin and Turner colluded in a plot to kidnap Finn, with Andrea as a willing conspirator. The plan started with Benjamin posing as an addict to get Kaylee to sell Finn to her, only for Kaylee to turn him down. Afterwards, Turner committed the abduction, with Finn being left at Andrea's sister's home--a convenient place to pick him up.
The plan to confront the couple was sidetracked by Kaylee, who went on her own and threatened them with a knife, while demanding Finn. While the couple was in denial at first, Andrea revealed her villainous role when she lambasted Kaylee and accused her of being a bad mother to Finn, after which Eric and Zara attempted to calm Kaylee down. Turner arrived with police and arrested not only Kaylee, but Eric and Zara as well, though later on, the pair confronted Turner regarding his role in the abduction, with Turner confessing and revealing the location of the couple. Andrea and Benjamin were set to take Finn and escape before Cri-Res arrived, and during her confrontation with Eric, the evil Andrea lambasted him for helping Kaylee, referring to her as a "horrible girl" and originally turning down Eric's plea to return Finn, claiming that she loved him. After Kaylee appeared and pleaded for her son, Benjamin pointed a gun at Eric and Kaylee, with the former continuing to plead with the couple to do what's right for Finn. At that moment, Andrea told her husband to put down her gun, and after Finn was returned to Kaylee, the couple was arrested (off-screen).