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—

From the white sky, the snow fall and running down her cheeks. We were holding hands, lying on the snow. When our eyes met, she smiles at me―― ――That was the dream I saw when I was a child. On the day when the town turned white by the snow, me and my childhood friend Mirai lying on the snow. I wanna stay as it is. That was what I thought when I was young. I grew up with a faint love. I was certain that our feelings were the same. Until that day. "Sorry. I'm sorry, Aoi. But... I'm sorry." It wasn't supposed to be like that. It wasn't supposed to be that way. She was the only one who support my heart, of me who doesn't dream of a great one. I thought she would be with me no matter what. But she went away. Feeling despair of everything, getting up from bed becoming troublesome. I started to having doubt on "reason for living in this meaningless world"―― Then I, had this particular dream. Beautiful coast. White sand beach, calming pale pink sea, a lighthouse that can bee seen in the distance―― ――"She" was there. Mirai's look alike, an ideal girlfriend who will never betray.