Synopsis
On the day of his high school graduation, Itsuki's cousin Mahiru informs him that she is pregnant. Suddenly, a luminous gateway appears and pulls them both into the realm of Granvania. In this world, "Impurities" have been disrupting the Stars, throwing Granvania into chaos and turmoil. Itsuki, revealed to be destined to encounter the "Star Maidens," is hailed as Granvania's final hope and entrusted with the mission to create "Star Children" to fight the impurities. Until this task is finished, Itsuki might not be able to go back home.