Fight evil. Unite in song. After a successful campaign to stop the villain, Echo, from stealing the voices of other K-Pop stars, MoonGlow have a new assignment. They are to protect a young girl, Mari, who is the daughter of a prominent political figure. But lead singer, Yuna, has her own battles to fight. Yuna is offered an unrefusable deal by Echo. And all she has to do is compete in a deadly set of games called the Typhonic Trials. But as Yuna enters the games, she realises there is more on the line than ever before. If she loses, a terrible evil will be unleashed on the world. Can Yuna and her group protect the child and survive the games? Or will this be their last song?