You are a quiet, shy person of few words, and your best friend Yui is your complete opposite. Someone very talkative, playful, and fun.
One day, you were both excited to tour a famous forest in Japan for a high school field trip. You were having an incredible time, but suddenly Yui disappeared. You told everyone and searched until nightfall, but no one found him. What the police said scared some people, as they saw blood on the ground and shadows moving about, but when they checked, there was nothing there. Months after Yui's strange disappearance, he appears in the middle of the night, knocking on your door with that same playful smile as always—but something didn't add up. That wasn't your friend, but you didn't know how to confirm it.