Imamiya Satoshi, "Sasshi" to his friends, has grown up in the Abenobashi Shopping Arcade in Osaka, along with his childhood friend, Asahina Arumi.
Now, all that was stable in his life is in ruins. His family's bath house has closed and been torn down, and Arumi's family is moving to Hokkaido - and taking her with them. In the midst of all this, something happens to the framework of reality, and Sasshi and Arumi slip into a weird parallel world. It's still Abenobashi, but not their Abenobashi. Strange things are afoot, and Sasshi must find out their meaning, in order to reach a goal that he barely understands.