In 1973, an alien species known as the BETA invaded Earth. In response to their seemingly endless numbers and resistance to conventional tactics, humanity developed manned bipedal machines known as Tactical Surface Fighters — a weapon system designed for the sole purpose of countering the alien threat. But TSFs alone weren't enough, and humanity has been trapped in a neverending war for decades, slowly but surely being driven to the brink of extinction.February, 2004: Professor Kouzuki's last-ditch gambit has failed, and Alternative IV is no more. The fate of mankind now rests on the success of Operation Babylon — a massive, simultaneous detonation of the mysterious “G-Bombs” over every single BETA hive on Earth.But in the blink of an eye, what seemed to be the hour of final victory for humanity in the decades-long BETA war turned into a colossal defeat. The alien invaders were seemingly destroyed, but at what cost? Europe and Asia were lost beneath the waves, and much of the remaining land masses are now barren deserts of salts, unfit for human life.The apocalypse has come and gone, but mankind remains. This is the story of the few who were left behind to survive on a dying planet. This is the day after.Lieutenant Tatsunami Hibiki is a stranger in a strange land. After a months-long arduous trek through the wastelands of North America, he has finally managed to reach Seattle, one of the last strongholds of humanity.But as he’ll soon discover, his trials have only just begun! There’s no love lost for refugees of the once proud and mighty Japanese Empire in this cruel new society, as the ever-present threat of famine looms over the survivors, and discrimination and civil unrest are now commonplace. Entrusted with significant command responsibilities for the first time in his life, and faced with a strange new world he hardly understands, Hibiki must find a way to keep the peace — and defend what little remains of Japan from the renewed threat of the BETA aggression.Will Hibiki rise to the occasion, or will his spirit falter before the greatest challenge he has ever faced?