Long ago, Equestria fell to the hands of a nuclear disaster. The inhabitants fled to the underground railway metro in hopes of survival. Now the surface is crawling with mutants, ready to dismember all people who dare thirst for the daylight.

Taro, a semi-famous stalker, travels through the metro alone, until he finally settles in a station for a break, there meeting a new friend. Her nature, though brash, forces him to look back on his two years of roaming and wonder what he could have changed. Together, the two travel the metro, meeting friends and changing the dangerous metro system.