Whilst looking for a hotel, the girls wind up at a creepy looking castle run by a one-hit wonder idol named Sakiko Kirumiya. Intrigued by the alleged luxury lifestyles one-hit wonders have, Milky Holmes decides to enter a swimsuit contest stamp rally so that they become ones themselves. Meanwhile, Sakiko, learning that Marine has no intention of staying as a one-hit wonder, traps her in an iron mask, hoping to keep her as one. After getting all but one stamp with help from the Feathers, Milky Holmes confront Sakiko, who is possessed by the third Element, Shout, in a Rock Quiz show, earning their final stamp, while Marine's desire to continue singing breaks her free from her mask.