Episode four 旁觀者與深海的詣見 The Bystanders and the Ambassador from Deep Sea —1—夢魘。邀請函。遺失的寶石。The Lost Gems —2—南港。天之光。結婚周年禮。The Presidents of wedding anniversary —3—人魚。水族館。騎士資格賽。The Qualifying Round to Be a Knight —4—疑團。薔薇釦。記憶的回音。The Echo of Memory —5—骸骨。人魚港。深海的輓歌。The Dirge from Deep Sea