Outlet - An Undertale story

Nine months, seventeen days, and 11 hours ago my sister went missing. She vanished, no trace of her was left behind. She just- just disappeared... And now, there she stands in her blue hoodie and a red scarf wrapped around her neck. Madison Locket goes missing for almost a year and returns telling tales of monsters who live underground. Her sister, Rachel, thinks she's gone mad. Madison tries to prove it to her sister, but slowly, she too starts to think she's crazy.