4. Underground Fortress

On MultiEarth Σ3302, a series of bizarre incidents occur where vital facilities vanish one after another! Reiji, dispatched to the scene, encounters the Galaxy Federal Police investigative duo: Mikuro Arimoto and Shoko Hanemura. Though shocked by Arimoto's seemingly impossible existence, Reiji begins investigating alongside them. Soon, Reiji and his team arrive at a mysterious underground fortress, only to be attacked by the culprit's drill machine and find themselves in a pinch...!