Airara repeatedly falls into the same mysterious dream, in which an unopenable ancient door keeps sending her signals. Following the guidance of the circle and wave symbols in her dreams, she travels through villages, an old chapel, and ancient castles, unearthing a wooden box, a bronze bell, and a split key. She meets Lena, who is also summoned by the dream, and the two piece together the clues to solve the mystery of the double key. This quest spanning reality and dreams finally reveals that the road was never meant for one walking alone — connection is the true answer to the riddle.
