Glass no Hana to Kowasu Sekai

Dual and Dorothy work as security programs inside the Box of Wisdom, deleting entire simulated worlds whenever a virus threatens the system. Their mission is clear and endlessly repeated until a massive corruption is destroyed and leaves behind a girl named Remo, an unknown program with no memory and none of the signs that would make her an enemy.

Instead of deleting her, the two help Remo search for her purpose, and she leads them into worlds they once observed only as targets. For the first time they visit digital cities not to erase them but to experience food, landscapes, and memories created inside. Each new moment makes their old duty harder to perform without question. If protecting the system requires destroying complete worlds, what exactly are they protecting, and why does Remo's forgotten existence seem tied to the answer?