A Wind Named Amnesia / Invader Summer by Hideyuki Kikuchi

In this science fiction novel, the world is plunged into chaos when a mysterious wind erases the memories of the entire human population, leaving society in ruins. The story follows a young man named Wataru, who, unlike others, retains his memories and embarks on a journey across a desolate America to uncover the truth behind the catastrophe. Along the way, he encounters various survivors, each grappling with their lost identities and the remnants of civilization. As Wataru navigates this new world, he confronts existential questions about humanity, memory, and the essence of self, ultimately seeking a way to restore what has been lost.