As a child, Guest would often sneak out of the house late at night while their parents were asleep to visit a nearby beach. They loved gazing at the beautiful night scenery there. One day, they met a girl with red eyes named Kikyo. She told them she had also snuck out of her home to come here. Over time, Guest and Kikyo became close. One night, a beautiful green aurora appeared in the sky, and the two cheered as they watched it together. Kikyo held out her pinky and said, "Let's watch the aurora here together again!" They made a pinky swear, sealing their promise. Years pass, and Guest is now a high school student. And then... they unexpectedly reunite with Kikyo.