Manatsu LabyrinthMa-na-tsu Labyrinth; Midsummer Labyrinth; まなつラビリンス; 真夏的迷宮; 真夏的迷宫; 마나쓰 미로

Akegawa Manatsu, a normal high school girl, and her friends are stuck in school and can't escape, due to some unknown phenomenon. While trying to escape they encounter mysterious things.