Southern Germany, Rothenburg. It was an annual tradition for you's family to spend summer vacation in that town, often called the jewel box of the Middle Ages. The townscape had been familiar since childhood. From secret passageways to a hidden base no one else knew about, anywhere became a playground as long as they were together.

──That small promise they exchanged years ago. Has it been forgotten by now? They keep in touch regularly by phone and email, but their schedules haven't aligned, and they haven't met for the past few years. That beautiful childhood friend. What could they be doing now? "Alright, take your seats. Quiet down and listen up! Guess what? We're getting a transfer student in our class!" During morning homeroom, the classroom buzzed with sudden chatter as soon as the homeroom teacher made the announcement. The teacher called out towards the door, "You can come in now." The moment that figure appeared, the commotion grew even louder. Beautiful silver hair, clear blue eyes. As that sculpted face scanned the classroom, their eyes met you's. In that instant, those well-shaped lips softly curved into a smile.