In a parallel world where the Japanese government exerts control over train operations, the Japanese National Railway (JNR) stands as a pillar of stability. Naoto Takayama, a fervent train lover seeking security, joins the JNR with dreams of becoming a conductor. Tasked with training under the Railways Security Force, he faces trials beyond just trains, preparing to tackle any potential threats. Placed in the Fourth Guard Team, Takayama partners with the acrobatic Aoi Sakurai, the genius Haruka Koumi, and the ever-hungry Shou Iwaizumi. Together, they confront minor crimes, infrastructure hurdles, and the radical group ''RJ,'' striving tirelessly to safeguard Japan's railway system and its prosperity.