When Kanzaki Shuuichi awoke, it was a perfectly ordinary morning.
His completely unremarkable home, the familiar route to school...

Something was wrong. Wasn't this summer supposed to have ended—?

When he reluctantly headed to school, they were there for some reason.
The 'Deadly Girls' who should have vanished from this world. They themselves were right there.

Apparently, they didn't remember anything about that summer.
Not only that—they didn't even remember Shuuichi himself.

They stood there as if they had never died, as if they had simply lived their destined lives all along.

Why were they here?
Why was he the only one who remembered?

Without understanding anything, a strange school life with these girls who knew nothing began to unfold—