The Hyakkaou Academy Guardians Society is an alumni organization meant to protect and guide students. But while they carry the beautiful and lofty title of “Guardians,” their real methods involve violence and oppression—and they’ve abducted Kirari Momobami while planning to abolish the student council presidency! Now it’s up to Yumeko and the newly assembled student council to win her back. The curtain rises on a field trip like no other…the Gamble Cruise!