Yozakura Quartet Vol. 21 (Kodansha, 2018)

Senate executive, Shiina, has been turned into a demon by Enjin, descendant of the Hiizumi branch family. After failing to rescue their friend and comrade at Enoshima island, the gang regroups and readies to meet her again on land. This time, the plan is to lure Shiina to Sakurashin and attempt to tune her while an all-star lineup keeps her at bay. But just when it seems like they might save her, an unexpected development occurs! The fallen genius arc reaches its dramatic finale!