Young Thiuri is about to become a real samurai, and his final test is to spend the whole night alone in a chapel, unable to speak or open any doors. But the appearance of a man disrupted everything. He asked Thiuri to help him deliver a letter from the king, and the recipient who was fatally injured asked Thiuri to deliver this important letter on his behalf. An adventure is about to begin. Can Thiuri deliver the letter in time? And what exactly is the content of that letter?