In 1973, alien invaders known as BETA nearly drove mankind to extinction. In response to this unstoppable threat, large humanoid arms called Tactical Surface Fighters were developed and deployed across the globe. After 30 years, the war continues with no end in sight, until the UN proposes a joint development program between Japan and the U.S.: The Prominence Project. Yui Takamura and Yuya Bridges, two pilots who have never met, soon find themselves recruited to take part in a new age of battle.