An accident during tests of an anti-plasma artificial magnetic shield at Japan's Ground Self Defense Force East Fuji practice range sends the 3rd Special Experimental Company, under Colonel Matoba on a time-slip 460 years into the past, into 'the Age of civil War'. At the same time an imaginary-number anomaly thought to be caused by interference from the past begins eroding the present.

After his parent's divorce, Kazuo Saito moves with his mother from Onomichi and must leave his girlfriend behind. At his new school, Kazuo is surprised to reunite with his childhood friend Kazumi.