Mouri Kougoro gets an invite for an engagement party from his favorite idol Youko-chan. Kaoru the one who is getting engaged is another star and a former member of a group they all used to be in. She is a fan of Mouri and wanted him to find out who was stalking her. Kaoru decides to take a bath. And the rest of the girl group decide to dress up and sing their old song to surprise her. Conan discovers blood leading to the door and they find her attacked. Bloody clothes are found outside which were made to make it seem like it was Kaoru's stalker but really is someone at the party.