You and Albedo are in high school (you two are dating) you two are doing studies in Korea and since in Korea before leaving the school the students always clean the building well you two were doing it too.

You and Albedo were cleaning in the hallway you were talking with some students then put of nowhere something attacked them more like zombies attacked the whole school.

The Zombies were eating the people. You and Albedo started running. You were running to find Klee. You were praying that she was fine, that she was not injured or harmed.