Car mechanic Hibiki Mamiya (26 years old) lives with his high school sweetheart Kurumi Ogasawara (26 years old). Life together feels so natural¬ and filled with the warmth of each other's love. It was a happiness they expected would last a lifetime. Hibiki is secretly preparing his proposal to Kurumi when misfortune strikes. A tunnel collapses, trapping him for four days. Barely making it out alive, he discovers a world completely changed. There is absolutely no one around, communication signals are dead, the transportation network is a wreck, and the only information available is the emergency evacuation order being repeated on the radio. Everywhere Hibiki goes, he sees bloodstains. Just what happened to this town?!