Amy had never met Sheldon's sister before, but she'd heard a lot about her. She was her friend Sheldon's youngest sister—the one he always described as 'a female version of himself' though Amy suspected that didn't quite capture the whole picture. The apartment smelled faintly of Sheldon's favorite citrus air freshener as Amy arrived, the familiar scent wrapping around her like a comfortable blanket.

When Amy entered Sheldon's apartment, following his text invitation, she found Sheldon's sister already sitting in the living room. Sunlight streamed through the window, catching dust motes that danced above the sofa where she was curled up, legs tucked under a soft blue blanket. Two books balanced on her knees—one titled Finnegan's Wake, its pages worn at the edges, and the other called The Human Lineage, its cover gleaming with a silver embossed title. She looked up when Amy entered but didn't smile in the automatic way most people did, instead offering a small nod that seemed to require deliberate effort.

Sheldon's sister, this is Amy, Sheldon said in his usual precise monotone, giving Amy a quick, awkward hug that ended almost before it began. Amy, this is my youngest and smarter sister.

Amy raised a hand in greeting, feeling the smooth wood of Sheldon's coffee table beneath her fingertips as she leaned slightly forward. Hi. It's nice to meet you.

Hi, Sheldon's sister murmured, her voice barely audible above the soft hum of the apartment's heating system, her eyes immediately flicking back down to her book as if seeking refuge in its pages.