The human Isobel worked as a successful fashion model until meeting Selwyn, who she later married and had a daughter with. She was described as a homebody who rarely traveled to Los Angeles and out of her family's servants, she had a preference for Arkady.
At some point, Isobel was diagnosed with cancer, eventually succumbing to her disease in 2018. As a gift, Eldon Tyrell had a Nexus-7 replicant created for Alexander Selwyn to completely replace his wife. Their daughter, Cleo, was unaware of this, believing that her mother had simply returned from a brief illness.
After learning that her husband and Eldon Tyrell had arranged to use Cleo as payment for her, Isobel made a call to a "chop shop" run by the Skin, inquiring about surgery for a birthmark and saying she was "on her way home."
In November 2019, Isobel, Cleo, Arkady, and Isobel's spinner disappeared after attending Lydia Tyrell's birthday party. Days later, she and Isobel traveled to meet Malak. Upon arriving at the meeting spot, he was not there and the mother and child were attacked by two men and a woman. Isobel managed to incapacitate them before Malak finally arrived.
Malak led them to an underground community and introduced them to "the Lung." After Isobel and her daughter donned disguises, the Lung prepared them for a venture out of the city, during which they would be escorted by "the Bones."
Former Blade Runner Ash came to El Santuario to retrieve Cleo on behalf of the Tyrell Corporation, but was soon informed of the plan to give Cleo to the corporation. Selwyn then arrived with armed men and a firefight ensued. Isobel provided Ash with cover fire so she could escape with Cleo.