After disaster in 2024, seven years ago rain has never stopped in this city.

As of recent, nightly serial killings have infused fear in human hearts.
Injured by monster attack and dying student Shouji meets girl Ai who binds a contact with him and gives him power to use mighty claw in battle.

They promise each other to survive no matter what, but it might be the first step to brighter future for the humanity.

[From vndbreview]