Today is Paris' music festival, Marinette and her friends are all setting up at the Couffaine houseboat. Juleka's mother, Anarka, will direct the stage. However, Marinette worries about Adrien, since his father has isolated him again after making a mistake in his piano act. In spite of Alya's reassures, Marinette goes to find Juleka's brother, Luka, and discovers they share similar hobbies and feels attracted to him. When Luka practices the guitar recital, it causes a huge sound wave creating a disturbance in Paris, which prompts Officer Roger and the police to disqualify Anarka's stage performance otherwise. Upset and disoblige, Anarka is akumatized by Hawk Moth and becomes Captain Hardrock, a pirate who wants to blast her music across Paris, ruining Jagged Stone and XY's concerts.