Practice runs for the new railgun, Mega Shot, are conducted in Anri's hometown. That's where Anri has an unexpected reunion with her childhood friend, Mizuho.

Mizuho begs for them to cancel the practice runs. She insists that the removal of the shrine for the installation of the Mega Shot will awaken Dorgo, the local guardian god, but Anri finds it hard to believe.

However, during the practice there's a big earth tremor...