These young girls' hearts are pure, and then violent!

The innocent and naive Mato. The mature Yomi. Seemingly opposites, but the time they spend together only strengthens a growing friendship.

But as they go into their second year at the school, they get placed in separate classes, and they begin to grow apart.

But somewhere simultaneously...

In another world, a young girl, blue fire residing in her eyes, Black Rock Shooter faces another young girl; this one holding a jet-black scythe, Dead Master, and a battle to the death begins to unfold.