"Secret of Immortality" is an ancient song composed by Mo Ming Qimiao's original music team, which tells a story of loss and recovery. The protagonist of the song breaks into the Tenth Palace and brings her back, making a promise to live up to. There are many mysteries in the lyrics of the song, such as "Golden elixir becomes perfect, Yuanying transforms", "Bagua chess performance, nine palaces resentment", "Wonderful world thousands of feet away asks the marquis", "Immortality begins with foundation building, immortality and demon end" and so on. These mysteries all refer to the characters and plots in the game.