A beautiful girl in a swimsuit releases a water gun! Girls Splash Action! A Trench Walker, an extraterrestrial lifeform that walks on the seabed, suddenly flew to Antarctica. Due to their planet modification, the sea level rose by 70 meters, and Japan and Tokyo and other large cities were submerged. In addition, the water on earth began to be converted into “water of the gods,” or Nectar, and those who could not adapt to Nectar were likely to die... In the meantime, a handful of girls who could adapt to Nectar boarded a submarine and went to the battlefield to retake the Earth back in special equipment.