群青戦記 グンジョーセンキ

At Seitou High School in Shiga Prefecture, a sports powerhouse, history enthusiast and archery club member Aoi Nishino feels out of place in the modern world, yearning for the Sengoku period. During after-school club activities, a red rain falls, and a thick fog engulfs the school, suddenly transporting the entire campus to the war-torn Sengoku era. As grotesque samurai invade the school and Anzuchi Castle looms outside, Aoi encounters a young Toyotomi Hideyoshi, using his historical knowledge to navigate the chaos. Athletes from various clubs—archery, kendo, football, baseball, and table tennis—band together, leveraging their skills to fend off attacking warriors. The students face the harsh reality of survival in a brutal era, clashing with historical figures in a desperate fight to stay alive. (Unreviewed summary by Grok 3)