Hakoniwa Yuugi(2014)

Hakoniwa Yuugi

Six years have passed since the grade schooler Manato disappeared during a school trip. Now his little sister returns to the city where everything started and meets an old friend of her brother, Atsuma, who is happy about her coming back. But the happiness doesn't last for long since Manato's former classmates are suddently getting attacked by some unknown enemy who wants to see them dead.