Sheila Porter is the biological grandmother of Noah Porter-Benson and the mother of the late Ellie Porter. At some point after Noah was adopted by Lt. Olivia Benson, Sheila would attempt to contest Olivia's custody over him before eventually deciding to abduct him.
While investigating a case, Trevor Langan approached Olivia in her office, telling her that Noah has a grandmother and that she is filing for custody. Olivia, clearly distraught, asks him to leave. Eventually, Sheila comes to Olivia‘s apartment and confirms who she is. At first, the two fight for custody of Noah, but eventually, Sheila visits Olivia at a cafe and the two negotiate for Sheila to introduce herself as his grandmother to Noah. (SVU: "Contrapasso") The two later form a friendship and Noah grows close to Sheila. (SVU: "Complicated") One night, while Olivia is called out for duty, instead of calling Lucy, Olivia calls for Sheila to babysit Noah, which makes both Sheila, Olivia and Noah happy.
Relationship with Lt. Olivia Benson
Olivia and Sheila's relationship changed throughout the time they knew each other. In the beginning Olivia didn't like Sheila due to her randomly showing up at her home and trying to fight Olivia for custody of Noah. In court, Sheila began challenging Olivia's parenting skills due to the investigation with Child Protective Services. After Sheila mentioned wanting to be a part of Noah's life, the two meet at a café and both women state they want what's best for Noah. Sheila told Olivia about what happen between her and Elle and why she and her husband never got along with her daughter.
Sheila meets Noah one night and the form a tentative friendship despite Olivia still having some trust issues. It isn't long before they are sorted and Olivia invites Sheila to babysit Noah when she is needed to head in for work.
Their relationship changed however when Noah is kidnapped whilst shopping for winter coats when with Sheila. In the beginning, Sheila feigns ignorance, claiming to be as shocked as Olivia is, and watches as Olivia grows upset as her squad investigates who took Noah. As Olivia worried over Noah, Sheila began mentioning Ellie and going through it all again.
In the course of the investigation, it becomes clear that Sheila was behind the entire kidnapping plot, and was always intent on keeping Noah all for herself. Upon Olivia learning the truth, they rush to Sheila's home and find Sheila and Noah are not there, with the only thing missing being a photo of Ellie. The detectives began investigating Sheila, learning that she had been planning the kidnapping for some time with help from her gardener, Juan Ortoli.
Throughout the course of the investigation, they learn that Sheila's sister owned a cabin and after learning of the location, Olivia headed up by herself to confront Sheila. After Olivia arrived, Sheila knocked her down and stole her gun. Sheila held the gun on Olivia and refused to let Olivia see Noah. Sheila was not happy that Olivia had custody and as they are speaking, Noah wakes up and runs over to Olivia, upsetting Sheila. After getting Noah out of the cabin, Sheila cried that Noah is her baby boy and he's all she has left.
Sheila is then arrested and tries to apologize for her crimes, to which Olivia gives no response. As she is being taken away, she takes one last look at Noah and Olivia in distress and rage, finally broken at the combined loss of her attempt at rebuilding her family and her freedom.
After the events of the kidnapping, Olivia suffers PTSD flashbacks of her ordeal with Sheila, as well as getting Noah to safety. Noah also suffers nightmares and has to sleep with his mother, due to the trauma. ADA Barba visits Olivia, who helps her get over Sheila and tells her that she has been through worse. Olivia, however, is now protective of Noah and helps him to get over the trauma that they both went through. After Noah seems to be doing better, he still asks about Sheila, and Olivia implies she is in a psychiatric hospital. (SVU: "Pathological")