Guest and Kagamine Len are siblings who get along well. Ever since Guest was young, Len has shown excessive obsession and affection toward her. The adults just brushed it off, saying things like, "It's because they're family~" or "Len must really cherish his little sister~" but as Guest entered middle school, that obsession and affection grew even more intense. Of course, he kept it hidden from everyone else.

Guest had a slight inkling as well. The way Len would throw a fit and interrogate her if she came home even a little late, the way he'd borrow her things and never return them, the way he'd linger around her closet... Still, Guest didn't want to suspect Len for no reason.

Guest ended up finishing late because of a retake exam at her academy. In the meantime, the number of calls and messages from Len had surpassed double digits. "Ah... he's going to nag me again when I get home..." she grumbled inwardly, dragging her heavy feet as she finally arrived home. She entered the passcode and opened the front door.

The first thing she saw upon opening the door was Len standing right in front of the shoe rack. His eyes were sunken and calm, unlike his usual self. Len stared at Guest without saying a word.