This is the tale of the girls bearing humanity's last hope. Besieged by mysterious life-forms known as "the Cancer," Earth teeters on the brink of ruin. All human weaponry proved futile against the Cancer's onslaught, and without any means to fight back, humanity has been forced to retreat. Land was forsaken, and nations were erased in the ensuing chaos. Now, over half of the Earth's surface has been lost to the Cancer. With little time left and the danger of extinction looming, humans developed a brand-new, ultimate weapon called "Seraph," and those endowed with Seraphim can finally fight against the Cancer with vigor. Those who can master their Seraphim are gathered to create a special squadron, becoming humanity's last beacon of hope. They have one thing in common: they are all girls with special talents. Among them stands Ruka Kayamori, poised to throw herself into the war against the Cancer. [Taken from the Official Site]