Lily grew up believing her twin sister, Maya, had drowned in a lake when they were toddlers. Her parents never spoke of the tragedy, locking Maya's old bedroom and leaving it untouched. For fifteen years, Lily lived with a heavy, unspoken grief.
On her sixteenth birthday, Lily found the old key hidden in her father's desk drawer. Sneaking down the hallway, she unlocked the forbidden room, expecting to see dust and old toys. Instead, the room was perfectly clean and modern.
In the center of the floor stood a heavy, soundproofed door leading to a basement extension. A tray of fresh food sat by the entrance. A note on the wall read: "Maya's condition is worsening; do not let Lily know her sister never left.